Gabriel Jesus has scored the only goal as champions Manchester City beat Chelsea 1-0 at Stamford Bridge to move level on points with their Premier League title rivals and gain revenge for their Champions League final defeat.
City lost three times to Chelsea in the space of six weeks at the end of last season, including the Champions League showdown in Lisbon, but Pep Guardiola finally got the better of Thomas Tuchel in Saturday's contest.
It proved a big day for City whose cross-city neighbours Manchester United lost at home 1-0 to Aston Villa after a calamitous finish which saw their star player Bruno Fernandes fire a stoppage-time penalty over the bar.
After the two lunchtime fixtures, there were four teams - Liverpool, Man City, Chelsea and Man United - all on 13 points, with Liverpool playing in the day's late game at Brentford.
At Stamford Bridge, City were largely dominant and deservedly opened the scoring eight minutes after the restart through a heavily deflected Jesus shot.
That sparked the game into life as City missed two big chances and Romelu Lukaku had a goal ruled out, though Jesus's strike proved to be the difference as top-flight champions City inflicted a first defeat of the season on the European champions.
Tuchel shifted from his usual 3-4-3 to a 3-5-2 to accommodate Timo Werner and Lukaku up top for the first time and Chelsea struggled to get going.
Bruno Fernandes blazed a stoppage-time penalty over the crossbar as Aston Villa earned a shock 1-0 victory at a below-par Manchester United in the Premier League on Saturday.
At Old Trafford, Kortney Hause's 88th-minute header had put Villa on course for the surprise win, but the same player's handball then gifted United an opportunity to steal a point in stoppage-time, only for Fernandes to dramatically miss the target.
Fernandes had grabbed the ball and placed it on the spot ahead of his compatriot Cristiano Ronaldo and looked set to snatch his side an undeserved draw, but hammered his attempt into the stands, leaving United to taste their first league defeat of the season.
Australian Associated Press