Riyad Mahrez descended from the bench to beat Manchester City 1-0 over Chelsea, cutting the gap to five points from Premier League leaders Arsenal.
Drawn by Everton on New Year’s Eve, City faced further disappointment against the injured but enterprising Chelsea side at Stamford Bridge.
But less than three minutes after arriving as a substitute with an hour left, Jack Grealish determined Mahrez the victor, which kept Arsenal firmly in their sights.
He also inflicted another defeat to Chelsea, still looking unconvincing under Graham Potter, but despite the double injury blast he gave City a lot of trouble, especially in the first half.
Without six players, including Reece James and Mason Mount, the evening started badly when Raheem Sterling was caught by his former City teammate John Stones in the opening moments and limped off.
He was replaced by Pierre-Emerick Aubameyang and initially the substitution did not put Chelsea off their feet, and when Kai Havertz played for Christian Pulisic, only one last interception from the Stones blocked the opening goal.
“It never rains, but it rains,” Potter said while discussing the injury list before kick-off, but it was monsoon season for the Blues when Pulisic, still feeling the Stones’ struggle, limped off with just 20 minutes on the clock.
Still, they attacked, with young substitute Carney Chukwuemeka blocking a shot and forcing Havertz to rebound from Ederson with a rebound.
City threatened Ilkay Gundogan with a wide field goal in the last half of the first half before sending the ball to Erling Haaland.
The Norwegian looked confident that he would score when he tapped it with his right foot and nudged it towards the goal with his left hand, but the ball went away.
Still, Chelsea came painfully close to scoring when Chukwuemeka slammed into Kyle Walker and took a low shot that resounded into the close post.
Pep Guardiola made a double change at the timeout and replaced the right-back pair Walker and Joao Cancelo with Rico Lewis and Manuel Akanji.
There may be no change in offense, but the difference in the density of visitors was palpable.
Haaland took another shot from Nathan Ake Kevin De Bruyne’s center to the angle of the post and before the crossbar header.
De Bruyne then forced Chelsea’s then understaffed goalkeeper Kepa Arrizabalaga to make a good save with a low drive from the edge of the area.
Guardiola sent Grealish and Mahrez at the same time, and the double substitution was an immediate benefit.
Haaland fed Grealish from the left and Kepa surprisingly let the English winger’s low-mid run towards the far post, where Mahrez got himself a simple finish by dodging Marc Cucurella.
Unlike City, the Chelsea bench looked distinctly naïve, but Potter still replaced ineffective first-half Aubameyang with the young Omari Hutchinson.
Their best chance for an equalizer fell on another young substitute, Lewis Hall, who was shooting over the crossbar in stoppage time.
Thus, City kept the pressure on Arsenal in a title race that would be in the background for the FA Cup weekend, when these two sides will meet again at the Etihad on Sunday.