Who is Mauricio Pochettino? The former Southampton and Espanyol manager is also a former Newell's Old Boys defender. There he played for the great, mercurial Marcelo Bielsa, and he makes no secret of his Bielsista heritage and orientation. While Bielsa has become famous for some peculiar formations he used, like the 3-3-1-3, this is misleading. Bielsa believed the formation as a concept had been made obsolete by player versatility and in-game interchange. His primary influence on contemporary football has been his recognition of pressing as both a defensive and an attacking tactic. A heavy pressing system which seeks to prevent opposition players from having too much time on the ball to pick out passes, Bielsa realized, can also be the beating heart of a "vertical" attack. Win the ball, and while the opposition has not regained their defensive shape, you make direct runs toward the danger zone for good opportunities.

Tottenham Hotspur fans have already seen an attempt to produce Bielsista football with this squad. While Andre Villas-Boas does not have Pochettino's direct lineage to the master, he was a young football nerd at the height of Bielsa-fever in football nerd circles, and his tactics are clearly indebted to Bielsa's vision. His oft-mocked discussions of "verticality" derive from translations of Bielsa's "verticalidad."

So, genealogically and philosophically, Pochettino looks like he is in continuity with Spurs' recent past. Still, talking about Bielsista football is all well and good, but what has it looked like in practice? I have stats from Pochettino both in Spain and England, and I'm going to compare him to AVB as well as to Bielsa himself, who managed Athletic Club in Bilbao for two seasons. This will provide both an overview of the effects of Bielsista football on the field as well as some possible areas of differentiation between Pochettino and his mentor and fellow student.

The Southampton Turnaround

The first thing that strikes me in Pochettino's record is that he was wildly effective at Southampton. The Saints had one of the smallest payrolls in the Premier League, and he steered them to a deserved 8th place finish. Perhaps more impressive is the job he did after taking over in 2012. Here we have a direct comparison, how did the side play under Nigel Adkins and then after Pochettino took over. The gap is huge, considering we're looking at basically the same team with the same players.

Nigel Adkins had the club playing sub-.500 football. That's good enough to stay in the Premier League, but it's lower mid-table stuff. Within just a few weeks of Pochettino's taking over, the Saints were putting up the expected goals numbers of a borderline top four contender. If you want something that can clearly separate Pochettino from AVB, this is it. This is one of the best possible markers of a manager's quality, that he can take over a club and effect quick but lasting improvements in their quality.

A Defense-First Manager

How did Pochettino build a better football team? I note that tactically, Southampton's attacking numbers look quite similar under Pochettino and Adkins. Southampton kept playing high numbers of through-balls and attacking through the center. They completed below average percentages of their passes. When Pochettino took over, his primary change was to institute the high press and make over the defense.

We can see this particularly in the rates at which opposing sides completed their passes. While Adkins was manager, Southampton's opponents completed a roughly league average 80 percent of their passes. Pochettino took that number down to a league leading 71 percent.





Pochettino's Saints prevent other clubs from stringing passes together to a degree that far outstrips any other side in the league. They continued the trend in 2013-2014 with another huge lead is opposition pass completion percentage. 73 percent topped the chart, with Spurs second at 78 percent.

The comparison to Andre Villas-Boas' sides is instructive. They both press, but it's much harder to complete passes against Poche's press. In particular, the Saints were able to break up play in their attacking half, in areas where there will likely be better transition opportunities. AVB's Spurs mostly exceeded the league average in breaking up play deep, preventing opposition clubs from completing passes in their final third.





Pochettino's sides broke up about 15% of opposition passes in their attacking half. AVB's Spurs were at about 10%, a little above average. No one else in the EPL broke 11% combined. The effectiveness of Pochettino's press at breaking up play is unrivaled.

Back to Spain

Pochettino's pressing success in England is unrivaled not merely by other English clubs, but also within Pochettino's career. His Espanyol sides were merely a bit above average at preventing pass completion. Indeed, even Marcelo Bielsa himself didn't get his Bilbao side to break up play at the rates of Poche's Saints.

To account for league differences, I've created a quick stat called Pass+. This compares pass completion rates to league average, and scales the result to 100. So a Pass+ of 100 is exactly average, 90 means that teams complete about 90% as many passes as league average. Espanyol were typically around 96-98, while Bielsa's Athletic Club tended to fall around 95.

When Pochettino was starting out with Espanyol, he didn't have a terribly effective press. But he improved it for the 2010-2011 season, and when Bielsa joined the league the next season, his Pass+ numbers stood up. Still, the big inflection point in the graph comes when Pochettino leaves Spain for the south coast of England. His club's solid, above average Pass+ numbers drop to world-beating lows. Even Pep Guardiola's Barcelona typically only averaged Pass+ numbers around 92-93, and here's Saints at around 90.

I'm not totally sure how to take this. Outliers make me skeptical, especially when they're outliers within a manager's career. But that's nearly 60 EPL matches where Southampton maintained their pressure. The data indicates that Pochettino has developed a better defensive press, one that makes it even harder on opposition attacks than either AVB and Bielsa could manage. He's putting up Guardiola numbers, but without anything like Guardiola talent.

(I should note here that opposition pass completion is a measure of pressing rather than a measure of overall defensive quality. Diego Simeone's Atletico Madrid were the best defensive side in Europe this last season, and they allowed very high rates of pass completion. I've compared Bielsa, AVB and Poche because they were all trying to play the high pressing game, and this gives us a measure of how effective they were at it.)

This Is Not a Direct Attack

The ultimate goal of Bielsista football is direct attacks immediately driven by defensive pressure. Even if pressing has taken a player out of his traditional role, he knows how to attack from anywhere on the pitch and immediately makes the correct run toward goal. As Spurs fans saw under AVB, this is not how it always works in practice. Many times when you win the ball back, the opposition is not so out of shape that you can drive straight down its center. Many times winning possession means that, well, now you have possession. AVB's Spurs were criticized for being slow in their buildup and failing to mount incisive, direct attacks.

Having gone over the numbers, I think there is something of a gap between the theory and the practice of a Bielsista high press. These clubs generally pass heavily outside of the final third, and they take more passes to set up shots than the average side.

I created two new stats to try to measure directness. The first is the number of completed passes per danger zone shot. I figure that directness requires aiming for shots from the danger zone, and not spending too much time completing short passes before you get there. The second is the percentage of pass attempts into the final third of the pass. Again, passes with targets outside the final third are unlikely to be part of a direct attack.

In 2013-2014, I have Southampton as one of the least direct attacks in the league by this metric. I feel pretty good about a measure of directness that captures Tony Pulis' and Sam Allardyce's clubs, while also recognizing that quality in the attacks of Manchester City and Chelsea. Being less than direct is not the worst thing in the world. Arsenal never rate that highly, and neither did Liverpool. But if you're looking for a club that moves to the danger zone with a minimum of fuss, that does not appear to be Pochettino's Southampton:

A number of pieces on Pochettino have suggested that he will differ from AVB by building a more dynamic and direct attacking force. I am struggling to find significant evidence of such a difference in the statistics. I am hopeful that Spurs will see some improvements, and I am highly skeptical that the terrible shot conversion rates that plagued AVB in 2013 (though not in 2012) will be repeated. But I would guess we'll see a lot of possession football, not all of it driving on for goal with speed and brilliance.

High pressing of this style, I think, is not conducive to constant, quick attacking. There will need to be build up play when possession is won in deeper areas, and Pochettino, like AVB and Bielsa, is happy to have his clubs play possession and retain the ball in these situations.

There has been some talk about Pochettino's attack being more direct because of his use of long passes last year. Southampton did play quite a few long balls, it's true, but only last season, In 2012-2013 under Pochettino, they played about five percent fewer long balls than average. His Espanyol sides were usually around league average in the use of long passes. I think looking to the longballs for directness may be a mistake.

This does not mean that Pochettino's attack will be identical to AVB's. And I think the weakness of AVB's attack can be overstated, especially if you accept the research on shot conversion rates. But there are some moderately worrying signs. In particular, Poche's Espanyal side were consistently below average in the percentage of shots taken from the danger zone. Only last season with Southampton did he finally get his club's shot selection to focus on higher expectation attempts. Before 2013-2014, Pochettino sides typically had a DZ% about 10-15% below league average. AVB tended to average about 20% below league average, so he was an extreme case. Hopefully Poche's more efficient attack with Southampton last year marks a change in strategy, and we will not see so many low-expectation attempts from distance next season.

Attacks Through the Middle

One more new stat for y'all. I like this one. Cross:TB ratio. Just a simple ratio of the number of crosses attempted to the number of throughballs attempted. It gives a good indicator of how a manager prefers to break down an pposition defense, whether by spreading the ball wide and pinging in crosses or by working through the center and looking for the killer pass down the teeth of the defense.

Pochettino's Southampton were not as ideologically strict as Liverpool and Arsenal in eschewing the cross, but they clearly preferred the attacks through the middle when possible. This will be a departure for Tottenham, who rate among the more traditionalist sides in the league.

This is a pattern for Poche, and in fact before 2013, he might have been better characterized as a bit of an ideologue for the through-ball over the cross. These are his career Cr:TB+ numbers, normalized for league context. Even in throughball mad Spain, his sides stood out as particularly focused on making these killer passes through the center.

Conclusions

I feel I have a better sense of Pochettino as a manager after going through his career numbers. This is a defensive manager first, a man with a complex high press that may be one of the most effective in the world. His clubs break up play all over the pitch at rates that dwarf even those of other pressing managers. His institution of the high press for Southampton took a previously lower-mid-table club very close to European contention.

Poche's clubs attack mostly through the center, though he isn't above using width and crossing. His clubs play many more throughballs than did Spurs in 2013-2014, and we should see a return to those creative passes and runs off the shoulder of the last defender. That said, his teams will play possession and I would not be surprised if we see some 1-0 or 0-0 results that call to mind AVB's Spurs. When you fight for and win possession as much as a Bielsista club does, sometimes there is not a lot to do with the possession in the position you find yourself. This was clearly something of an issue for both AVB and Bielsa himself, and Pochettino's Southampton side could find themselves passing and passing with no obvious solution sometimes too.

One Last Stat: What's Up With the Chipped Passes?

This one I don't have an explanation for. But throughout his career, Mauricio Pochettino's sides have played more chipped passes than other clubs in the league.

His clubs have almost always played 20 percent more chipped passes than the average club in their league, and last year Southampton approached 50 percent more chipped pass attempts. Perhaps the happy story we can tell here is the creative use of the chipped pass. Putting the ball over the heads of defenders and into dangerous areas. My data cannot tell me how effective the use of the chips are. But if I had to add one conclusion, I would say that I expect Pochettino's Spurs to be chipping the ball all over the place. It's what his clubs do.

All data provided by Opta.