1 Theo Walcott is able to seize his chance
Arsenal's players have been grumbling among themselves about what they perceive to be the preferential treatment afforded by the manager, Arsène Wenger, to Andrey Arshavin. The Russia forward tends to enjoy a roaming brief yet without the responsibility to track back, even in training. Wenger reasons that Arshavin is worth it because he has the capacity to change a game with one flash of genius. But even Wenger reached the end of his tether at Arshavin's non-performance at Manchester United two weeks ago. The Frenchman wielded the axe and presented Walcott with a glorious chance from the start. It was incumbent on Walcott to take it. Walcott's game is built upon making the difference, even if it is only in one or two flashes. In the space of two second-half minutes, he contributed an assist and a goal, his ninth of the season. Job done.
2 Cesc Fábregas has been sorely missed
Whatever the debate about where Cesc Fábregas's problem lies – is it in his hamstring or his head? – there can be no doubting his class when the whistle blows and he puts everything on the line. There was something gloriously reassuring at the Emirates about his return from the start to occupy the "hole" behind Arsenal's lone striker, in this case Robin van Persie. The midfielder showcased his ability to find pockets of space, even if he had to drop deep from his starting position to do so, while the weight and vision of his passing was delightful. An example? His pass for Theo Walcott's goal. Fábregas's determination to topple Chelsea was etched into his performance, from his throwing himself into the melee that preceded Alex Song's goal to his celebrations after his goal.
3 Chelsea's blip is far from over
When the defending champions puffed out their chests and raised the intensity against Tottenham Hotspur at White Hart Lane in their previous fixture, emerging with a creditable 1-1 draw, it felt as if they had turned a corner. Those predictions needed to be hastily revised after this, a disjointed and laboured display that was, frankly, dismal. Lukasz Fabianski was not required to make a save. Chelsea's manager, Carlo Ancelotti, could name the spine of the team he favours, with Frank Lampard back. However, the west London team looked anything but champions-in-waiting again. One positive was that they did not let their heads drop at 3-0 but it was scraping the barrel. It is now six points from an available 24 in the Premier League. "You're getting sacked in the morning," Arsenal's fans informed Ancelotti. The worry grows at Stamford Bridge.
4 Didier Drogba is mortal
The joke that used to do the rounds about Philippe Senderos, the former Arsenal defender, was that he would jump six feet into the air if you shouted "Didier Drogba" at him. Chelsea's Ivorian striker has enjoyed plenty of sport in tormenting central defenders in red and white and entered this contest with 13 goals in 13 unbeaten games against them. The respect/wariness towards him was shown early on when he rumbled through and Arsenal's defence backed off and backed off. He shot and saw the effort fizz just wide. Fábregas dared not even mention Drogba's name in his programme notes. "They have a player who loves scoring against us," he wrote.But this was not to be another of those nights when Drogba bullied and Arsenal meekly rolled over. Chelsea failed to get him into dangerous areas and it said much that his best moment was his taking of the free-kick that led to Branislav Ivanovic's goal.
5 Chelsea's resources look stretched up front
The pre-match news that Nicolas Anelka had withdrawn because of knee trouble shone a harsh light on the attacking options available to Ancelotti. In came Salomon Kalou but what of the substitutes' bench? Ancelotti was unable to name a single striker, with the attacking midfielder Gaël Kakuta the only offensive player on it. Fabio Borini is out of favour because of a contract dispute and is injured, while Daniel Sturridge picked up a knock in training. Chelsea's bench had four academy players and a grand total of two goals, both of them scored by José Bosingwa. Ancelotti says he will not buy a striker next month but can his team sustain a title defence and a tilt at the Champions League without a little extra help? David Hytner