(L-R) David Neres of Ajax, Hakim Ziyech of Ajax, Ajax coach Erik ten Hag, Donny van de Beek of Ajax during the Dutch Eredivisie match between Ajax Amsterdam and Vitesse Arnhem at the Johan Cruijff Arena on April 23, 2019 in Amsterdam, The Netherlands(Photo by VI Images via Getty Images)

Ajax’s run to the Champions League semis is more than just an inspiring underdog story. Erik ten Hag’s team are a for real.

It’s hard to imagine a more euphoric quarterfinal victory than the one Tottenham enjoyed against Manchester City two weeks ago. That was in part because they already knew who they’d be playing in the semis: This season’s designated Champions League knockout-round minnows, Ajax. Some Spurs fans already have one eye on the final.

Known for their young, exhilarating individuals — Frenkie de Jong, Matthijs de Ligt, Hakim Ziyech, et al. — Ajax are often viewed, quite patronizingly, as a talent factory for the elite first, and a football club second. Spurs are certainly not exceptions to this mindset, with no less than four Ajax alumni currently on the books and Barca-bound de Jong recently admitting he was very close to making it five last summer.

A high turnover of managers since the departure of Frank de Boer in 2016 has done little to dispel the perception of Ajax as a feeder team, but manager Erik ten Hag has earned respect for both himself and his club in the Champions League this season. Electrifying performances against three titans of Europe — Bayern Munich, Real Madrid and Juventus — have elevated the Dutch side above their customary recent status as the temporary home of the continent’s brightest prospects.

The time for underestimating Ajax is long over.

Two major tactical features have been vital to Ajax’s progression to this stage of the competition, and both will very likely be on display against Spurs. The first is what ten Hag has described with the Dutch/German term “variable pressing.”

“You could see that Juve were a little scared of us and so were Real Madrid,” ten Hag said following Ajax’s quarterfinal win against the eight-time defending Serie A champions. “It is very difficult to play against our style of football, as we have very technically-gifted players and it’s tough to press us. Even in defense, only we know how to perform that variable pressing game.”

The key to this style of pressing seems to be ensuring all 10 outfield players are perfectly in sync, knowing exactly when and where to dramatically change the tempo of their pressing. By inviting passes into certain areas — which leaves a lot of wide open space on the pitch — Ajax can target specific vulnerable players or zones where they believe they can win the ball. Opposition teams are lulled into a false sense of security by the Amsterdam side, who stand off the player with the ball, moving at a walking pace, before suddenly and collectively moving through the gears to win back possession.

A crucial component of this style of pressing is the participation of Ajax’s attackers when they’re ahead of the ball — a situation in which they would usually be considered out of the play. They have two objectives in these moments. One is to cut off backward passes from opposition players. The other is to make sure they’re in space to start a counter-attack in case one of their teammates wins the ball.

This pressing system places a much greater focus on players than it does on zones, meaning it can be exploited by good dribblers from deep. Emre Can, for example, had some success in the quarterfinal picking up the ball outside of Ajax’s pressure and beating the first man, which left him with a lot of space to break into.

Midfield ball-carrying has been a hot topic at Tottenham recently. The importance, decline and eventual sale of Mousa Dembele left a gap in Spurs’ midfield that has shaped the club’s form for much of the past three years. Former whipping boy Moussa Sissoko has, over the course of the season, conquered the role once played so well by Dembele, and is now a popular pick for the club’s Player of the Season award. He will play a key role against Ajax.

The question for Tottenham is less whether Sissoko can carry the ball forward when he has it and more whether he can safely receive it in the first place. For all his improvements, Sissoko’s first touch and ability to receive the ball on the turn remain weaknesses Ajax will look to exploit.

The second key tactical feature of ten Hag’s side is their uniquely narrow attacking game. The pressing system certainly helps with this, providing the platform for counter-attacks through the middle, but the decision to keep their wingers inside and their full-backs deep is one few clubs could make work.

With Ajax’s attack taking up little more than the width of the penalty box, the opposition tend to match them, compressing the space in the central areas in which Ajax’s counter-attack is so dangerous. This is where the technical and creative brilliance of their players — in particular, their ability to dribble the ball and combine with teammates under pressure — shines through.

Prior to scoring the winner against Juventus, and during the first leg of their round of 16 tie with Real Madrid, Ajax were criticized by some neutrals as being too wasteful. They entered the box repeatedly only to attempt a difficult pass instead of taking a shot.

This appears to be a function of their narrow attack. When an Ajax forward breaks into the box early, he drags multiple defenders with him. Since these defenders are in a narrow starting position, they’re often able to (at least partially) obscure the attacker’s sight of goal. However, this only leaves extra space for Ajax players making late supporting runs into the box, which then become very attractive options for the player on the ball. Hence their love of the “extra” pass, and the appearance of wastefulness. As frustrating as this method may appear, Ajax scored three goals against Juventus (with an xG of 3.3) and five against Real Madrid (wth an xG of 4.8). Clearly it’s working.

One final benefit of Ajax’s narrow setup is that it provides them opportunities to win back any loose balls created by their rapid attack, giving their counters a second wind.

The key for Tottenham here may lie simply in their ability to maintain composure. Ajax attack at a lethal pace, and it can be easy to get drawn into the panic. For Tottenham, it will be crucial to remember the basics and prioritize blocking shots over winning the ball back. Luckily for Spurs, this is an art Toby Alderweireld, especially, has mastered.

The final, and possibly the biggest, challenge for Tottenham comes not from the Netherlands but within their own squad. Spurs have suffered one injury crisis after another this season; May will be no different. Talisman Harry Kane will miss the semifinal with injury. Harry Winks, Serge Aurier and Erik Lamela are all doubts. Heung-min Son is suspended for the first leg. Sissoko, whose ball-carrying seems like it could be such a useful weapon against Ajax’s press, is likely to miss the first leg too.

Without him, Mauricio Pochettino’s best option may be to start three defenders, freeing up Jan Vertonghen to dribble out from his left-sided defensive role. Pochettino has also turned recently to playing Victor Wanyama, who now seems to be capable of playing a full 90 minutes without his knees buckling (provided, at least, he avoids breaking into anything beyond a light jog more than two or three times a match). None of this is ideal.

For one of these clubs, this tie will be historic, ensuring their first visit to Europe’s biggest game for at least two decades. It also promises to be a visual spectacle with both clubs committed to an aesthetically pleasing, attacking style of play. The key difference between the sides is the tempo they like to play at. Ajax will hope to create a hectic, end-to-end affair; Tottenham will be happy if they can assert a slow, steady control.