1 Manchester United's stubborn refusal to relinquish their title remains …

Manchester City ended up reopening a two-point lead at the top of the Premier League this weekend, though the manner of Manchester United's recovery from three goals down here left the champions sensing that the momentum remains theirs. This was one of their more daunting fixtures from the second half of the campaign, at a ground where they have not triumphed in the league in a decade. At 3-0 down, they had flirted with humiliation. Yet the brace of penalties converted by Wayne Rooney and Javier Hernández's third claimed what might, at times, have felt like a bonus point. Certainly, the sight of the Mexican scoring again was a fillip and the celebrations among the away support, prompting a salute from the retiring Rio Ferdinand, gave the impression that theirs was the greater sense of satisfaction.

2 … but their soft underbelly could yet cost them

The fragility that has flared at times this season in the champions' backline was exposed ruthlessly here. United might have considered Chelsea's rearguard severely weakened but they ended up pining even more for the absent Nemanja Vidic, or Chris Smalling and Phil Jones. The goalkeeper David de Gea seems to shrink at times – an outstanding save from Juan Mata's free-kick in stoppage time aside – and Ferdinand might have been closer to David Luiz for the home side's third, while Jonny Evans and Patrice Evra endured their own traumas here. Indeed, the manner in which the visiting captain was tricked and tormented by Daniel Sturridge just after the half-hour was disturbing. That the team still boast attacking flair in abundance is clear from the eye‑catching comeback but can this makeshift and inexperienced defence really claim a title?

3 Chelsea have something in reserve after all

The locals ended deflated, their lead having been eroded amid a flurry of goals, but they could draw some encouragement even from what felt like a wasteful draw. This had felt like a test of an emerging Chelsea. Almost half of what might be considered André Villas-Boas's first-choice side were absent either injured, suspended or on international duty – John Terry, Frank Lampard, Ramires, Ashley Cole and Didier Drogba were missing – to leave the lineup unfamiliar. Yet this squad are well into a process of rejuvenation, a revamp that will gather pace in the summer. In that context, to witness the hosts conjure a three‑goal advantage, and even threaten to run riot in the early stages of the second period, offered promise of better times ahead. Gary Cahill was making his first appearance for the club, and Michael Essien his first start of the term. Mata, operating centrally behind a striker here, is elusive and outstanding. Daniel Sturridge is a pest on the flank. There is promise, too, in a bench crammed with the youth of Oriol Romeu, Lucas Piazón, Romelu Lukaku and Ryan Bertrand.

4 Meetings with United can still conjure flashes of class from Fernando Torres

The Spaniard has been at Stamford Bridge for a year now and the goals are still not forthcoming, yet occasions such as this still seem to stir something in Torres. Memories, perhaps, of the days when he would have Vidic & Co quaking in their boots at the prospect of shutting him down. A first-half shot skewed at least two advertising hoardings wide of a post was that of a man with three Premier League goals as a Chelsea player to his name. The subsequent gallop from deep and the pinpoint cross for Mata to score Chelsea's second had the home support salivating. Confidence is still brittle , as illustrated by a reluctance to shoot where once he would have spat an attempt at goal, and he may no longer be the Spain international who consistently illuminates the Londoners, an honour that falls to Mata these days. But the management will still believe they can coax the striker back to form. Time to trot out the old line that one goal may bring a bucket load …

5 There is no escaping the controversy surrounding John Terry

The Chelsea captain was absent here still nursing a knee injury, the defender flitting around the East Stand reception prior to kick-off chatting amiably with members of staff as if he hardly had a care in the world. Yet, out on the pitch, reminders of his on-going court case were never far away. There were bellowed chants from both sets of fans, those directed by sections of the home support at Rio Ferdinand, Anton's brother, as vicious as they were unwarranted. The bruising on Terry's knee should recede soon enough (he may actually be paying now for an insistence that he was fit and able to play back at Loftus Road the previous week) though the allegations – which he denies – that have cost him the national captaincy will clearly tarnish high-profile occasions such as this for some time yet.