After handing Chelsea the title on Friday, Roberto Mancini watched his Manchester City side promptly snatch it away again as Carlos Tevez's second-half strike ended the champions' 100% record with a 1-0 win.
In a tactical battle, Tevez's moment of inspiration just before the hour proved to be decisive.
Chelsea were unable to halt his burst from halfway and he found the perfect finish too, through Ashley Cole's legs and in off the post.
Chelsea battled hard to force an equaliser, but, just as they had done for most of the contest, they failed to open up City and came no nearer than the header Branislav Ivanovic struck the bar with before half-time.
Tevez drifted away from Florent Malouda as he anticipated a return pass to Didier Drogba, who had just taken a corner and his movement gave Malouda the space to curl a deep cross to the far post, where Alex nodded it back to Ivanovic who could only find the woodwork.