Marten de Roon's stoppage-time header earned Middlesbrough a 1-1 draw at Manchester City on Saturday to leave Pep Guardiola's side in a vulnerable position at the Premier League summit, reports Agence France-Presse.
Sergio Aguero's 150th City goal looked to have sent his side three points clear, but De Roon brought the Etihad Stadium back to earth following Tuesday's brilliant 3-1 win over Barcelona in the Champions League.
City's slip-up means Chelsea can surpass them if they overcome Everton in Saturday's late game, while Arsenal and Liverpool -- both just a point off the pace -- will also have designs on top spot.
Second-place Arsenal tackle Tottenham Hotspur in Sunday's North London derby, while Liverpool entertain Watford.
Elsewhere, bottom club Sunderland ended their wait for a first win of the season at the 11th attempt by coming from behind to win 2-1 at Bournemouth despite having Steven Pienaar sent off.
Boro's trip to the Etihad reunited Guardiola with his former Barcelona goalkeeper Victor Valdes and the Spain international set the tone for his one-time mentor's day.
Valdes saved brilliantly from Aguero and David Silva in the first half, while Kevin De Bruyne shot just wide from Aguero's pass.
With half-time beckoning, the hosts went ahead in the 43rd minute as Aguero dispatched De Bruyne's sumptuous cross to register his 150th goal in 223 City appearances.
Boro showed more attacking intent in the second half, former City striker Alvaro Negredo almost catching out Claudio Bravo with a lob from his own half before Bravo saved smartly from Adam Forshaw.
And after Aguero had squandered a late chance to make the game safe, Dutch midfielder De Roon met George Friend's deep cross with a thumping header to earn Boro a dramatic point.
Sunderland remain bottom, below Swansea City on goal difference, but manager David Moyes belatedly has a victory to his name following a hard-fought success at Bournemouth's Vitality Stadium.
After Adam Smith had teed up Dan Gosling to bundle in an 11th-minute opener for Bournemouth, Victor Anichebe equalised with his first Sunderland goal.
Pienaar was sent off just before the hour after receiving a second yellow card for a lunge on Junior Stanislas, but Jermain Defoe netted a 74th-minute winner from the spot after Smith felled Anichebe.
There was late drama at Turf Moor as Burnley withstood a Crystal Palace fightback to prevail 3-2 courtesy of Ashley Barnes's 94th-minute strike.
Sam Vokes and Johann Berg Gundmundsson put Burnley 2-0 up, only for Palace to hit back through second-half goals by substitute Connor Wickham and Christian Benteke.
But in the fourth minute of stoppage time, Gudmundsson crossed for Barnes to fire home and condemn Palace -- who later hit the post through Andros Townsend -- to a fourth straight defeat.
Stoke City drew 1-1 at West Ham United, with Bojan Krkic exploiting an error by home goalkeeper Adrian to equalise in the 75th minute after a Glenn Whelan own goal had put the hosts in front.
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