1) Chelsea are vulnerable against teams that attack them

Chelsea's 3-0 loss to Sunderland yesterday came as an almighty shock, but a closer look at the champions' performances and results so far this season suggests it was coming. The accepted wisdom since Carlo Ancelotti's men thrashed West Brom and Wigan by six goals apiece in the opening two games of the season has been that this is a near-indestructible team on course to retain the title with something to spare. But since those heady summer days Chelsea have looked considerably more shaky, with a theme emerging – have a go at the men in blue and they are there for the taking. It started on 19 September when Blackpool responded to being beaten 4-0 at Stamford Bridge after the first half by continuing to attack and almost scored three times in the second period, through DJ Campbell, Luke Varney and Gary Taylor-Fletcher. Newcastle arrived in south-west London three days later, in the Carling Cup, and were fully rewarded for showing similar adventure when they won an exhilarating contest 4-3. Liverpool overcame Chelsea by going at them from the start and Blackburn came close to doing the same the week previously when they too showed no fear. Sunderland's approach was just as bold and had it not been for Petr Cech they might have won by an even greater margin. The champions would have, of course, put up more of a fight had Frank Lampard, John Terry, Alex and Michael Essien been available but Terry and Alex played against Newcastle, and Alex and Essien faced Newcastle. Next up for Chelsea is a trip to Birmingham and for their manager Alex McLeish the message is simple: Attack, attack, attack.

2) Manchester United's unbeaten run will end sooner rather than later

Unlike Audley Harrison, Manchester United recovered from a heavy blow to put up a fight on Saturday. Their 2-2 draw at Aston Villa was rousing stuff and kept up the club's unbeaten run, which now stretches to 20 games in all competitions this season. But there is a growing sense that the knockout punch is coming. United's midfield remains an area of weakness while with Wayne Rooney short of his best and Dimitar Berbatov sliding back into his trademark dormancy, their attacking threat appears questionable. The team has been boosted defensively by the return of Rio Ferdinand but even that area of the team looked vulnerable against a quick and direct Villa side that would have comfortably recorded a second league win in 30 attempts against Sir Alex Ferguson's men had they not panicked and retreated after going 2-0 up. United have a string of pretty straightforward games coming up, starting with the visit of Wigan on Saturday, but with fixtures against Arsenal and Chelsea to come before Christmas it seems unlikely they will enter 2011 still undefeated. This team are no invincibles.

3) Manchester City will not win the title under Mancini

Derek Trotter is not the obvious man to go to for advice on how to run a football club, but Del Boy's assertion that 'he who dares, wins' carries more than a touch of sense in this most open of title races. The leading pack are more vulnerable than ever and, as such, teams willing to take a chance are more likely to prevail. It seems remarkable then that Roberto Mancini, backed by millions and millions of Abu Dhabi cash and able to call on the likes of Carlos Tevez, Emmanuel Adebayor, Adam Johnson and David Silva should continue to send Manchester City out with the remit of being as dull and unadventurous as possible. The tepid derby draw with United was one thing but repeating the trick against Birmingham City, at home, is quite another. Although the sound of City fans booing a manager that has led their side to fourth may seem ungrateful, their frustrations are fair. What, after all, is the point of being the richest club on the planet if you play with zero ambition and considerable apprehension? City remain within reach of leaders Chelsea but with trips to Stamford Bridge, Old Trafford and the Emirates all to come this season they are likely to drop points against their title rivals and, if Saturday is anything to go by, will do the same against the supposedly lesser sides, too. Unless Mancini changes his ways or Sheikh Mansour changes his manager.

4) Elmander may be a top striker after all

Of all the reasons Bolton Wanderers supporters could find for deciding Gary Megson was not qualified to manage their team, few stood out like the purchase of Johan Elmander. The Sweden forward was signed from Toulouse for a club record £10m fee in June 2008 and, over the course of Megson's remaining 18 months at the Reebok Stadium, came to personify all that was ineffective and crude about his reign. After two full seasons at Bolton, Elmander had scored just 10 goals in 48 starts. He looked a total waste of money and time. But under the management of Owen Coyle, the 29-year-old is finally flourishing and against Wolves on Saturday scored a goal which justifies his reputation as a player of international class. Surrounded by five defenders, Elmander used five touches to pirouette through the crowd before calmly rolling the ball past Marcus Hahnemann and into the left-hand corner of the goal. It was the striker's sixth goal of the season (all away from home) and undoubtedly his best. Had Lionel Messi done the same, the world would have risen into a temporary frenzy. Maybe Megson was not so bad after all ...

5) Goalless draws can be worth watching

Given its increasingly mates-sat-around-at-the-pub level of analysis and, as was the case this week, later start, Match of the Day no longer feels like the must-see show it once was. But it continues to provide a service and Saturday's showing of West Ham's 0-0 draw with Blackpool proved a stalemate can be worth sacrificing sleep for. The fixture produced 42 shots on goal and while the fact none of them went in was principally down to an absurdly poor level of finishing by both teams, viewers cannot have faulted the entertainment on show. As Ian Holloway, the Blackpool manager, said: "That was a fantastic game which I would have been happy to pay to watch." Amid the madcap there were some high-quality performances, most notably from Scott Parker and Charlie Adam, and so while the home supporters may not have been satisfied with what they saw – many of them booed West Ham United off at the final whistle – those sat at home with Lineker, Lawrenson and Hansen for company cannot have had too many complaints.

• Now check out our Premier League chalkboard tactical analysis of the weekend's action.