City 1 - 0 Chelsea

• This feels like a marker. It might not be the biggest achievement of Roberto Mancini's career; that has to be the once in a generation win at Stamford Bridge last year. But it is his most significant. In September we are still in the window of opportunity for season-shaping wins, and this certainly looks like one. Beyond that, it is a empowering personal vindication for Roberto Mancini. If our defeat of Chelsea last December was the idealised Mark Hughes performance, this was an idealised Mancini display: as impenetrable defensive arrangement as I've ever seen from a City side, providing the platform for a piece of Carlos Tévez magic to win it for us.

• Chelsea have started this season unlike any Premier League side I can remember. If you include the final scenes of last season they had scored 38 goals in their last eight league games. But they created nothing from open play. Two close headers from set pieces and that was it. I have never seen a City side defend that well. The back seven (eight if you include Yaya Touré) held their shape perfectly, as well as all putting in a number of exceptional individual performances. Didier Drogba, snuffed out, was eventually replaced. Nicolas Anelka and Florent Malouda - the two musketeers who have blown away so many sides this year - were anonymous. Michael Essien was reduced to shooting from distance. This was the first Premier League game since Boxing Day in which they have failed to score, a run of 26 matches.

• We didn't create much more, either. It was a very cagey game, not unlike the 0-0 draw with Liverpool last season. But unlike Chelsea we capitalised on our one opening. Yaya Touré won the ball in midfield and fed Carlos Tévez, breaking from inside our half. David Silva persuaded John Terry not to commit to Tévez, who found enough space to shoot through Ashley Cole's legs and into the bottom corner. This is becoming a key part of how we win under Mancini: establishing a sound defensive platform and waiting for Tévez to do something special. In an ideal world we'd create more chances playing thrilling football with a fluid movement of all outfield players. But it's not like there's a bad way to beat Chelsea.

• From that point the game opened up a touch. Chelsea committed bodies forward but never looked like breaking through. We threatened more as Yaya Touré started driving forward into space. We might not have created that much, but neither did Chelsea. Danny Sturridge, Yuri Zhirkov and Josh McEachran came on but there was still no breaching the Barry-de Jong-Kompany-Kolo shield. Joe Hart barely had a difficult save to make. If you want an example of what Roberto Mancini has brought to City, what he's all about, then this is it. That's two goals conceded in nine games with this team now, and one of those was a freak. It takes some adjustment - it doesn't feel right - but we have to confront the possibility that we have the best defence in England.

• Now I can cope with the Blackburn draw and the Sunderland defeat. I can even cope with the limited side we put out on Wednesday night. I said I would have put Vincent Kompany and Nigel de Jong out at the Hawthornes, and while I maintain a greivance on this issue, I can certainly see that they looked well rested and fresh today. Had they played in midweek things might well not have turned out this way. In this regard, and in others, today was a striking personal vindication for Mancini.