Diego Costa snatched an injury-time equaliser to secure Chelsea a 1-1 draw against Manchester United and preserve the Premier League champions' unbeaten run under Guus Hiddink.
Louis van Gaal described United's performances against Derby County and Stoke City as "sparkling" and his side began Sunday's game in dominant fashion at Stamford Bridge, though chances were few and far between in the first half.
Kurt Zouma was carried off on a stretcher shortly after half-time with what looked to be a serious injury to his right knee and Jesse Lingard turned home in fine style just two minutes later to put the visitors ahead.
David de Gea made a handful of superb saves to keep Chelsea at bay in the reverse fixture at Old Trafford and he frustrated Hiddink's side again, making terrific stops against Branislav Ivanovic and Cesc Fabregas in particular.
As a first Premier League win in seven over the champions for United neared, Costa pounced in the dying minutes to preserve Chelsea's unbeaten run since Jose Mourinho was sacked, which now stands at 11 games in all competitions.
United controlled the opening quarter, Michael Carrick drawing a low stop from Courtois before the Belgian superbly clawed away Anthony Martial's effort after cutting into the left channel.
The visitors kept up their pressure as Chelsea struggled to gain a foothold in possession, though De Gea had to react smartly to catch Nemanja Matic's glancing header from Willian's delivery.
Costa placed a low shot narrowly wide of the far post as Hiddink's side suddenly began to look a real threat, with Oscar then blazing over the bar from close range after being teed up by Cesar Azpilicueta.
Wayne Rooney almost turned home Matteo Darmian's drilled cross but John Terry had shouts for a penalty waved away in the final minute of the half as his shot on the turn took a slight deflection off Daley Blind's raised arm.
Rooney drew a strong save from Courtois and Martial dragged a shot narrowly wide as United began the second half back on the front foot, with the Belgian again at full stretch to keep out Lingard's curling effort.
Hiddink introduced Eden Hazard from the bench but was forced into a second substitution within a minute after Zouma had to be carried off on a stretcher after jarring his right leg when landing awkwardly near the centre circle.
Chelsea's defence was slow to settle after Gary Cahill's introduction and Lingard capitalised superbly to put United ahead, controlling Cameron Borthwick-Jackson's low cross from the left and firing into Courtois' top-left corner on the turn.
De Gea reacted brilliantly to tip Ivanovic's volley over the bar as Chelsea sought an immediate response, and the Spain international denied compatriot Fabregas with another fine save to keep the midfielder's effort out of the top corner.
United's resistance was finally worn down in the first minute of stoppage time, however, as Costa capitalised on Blind's slip to finish at the second time of asking and preserve Hiddink's unbeaten run.
Key Opta stats:
- United have won just one of their last 14 Premier League visits to Stamford Bridge (D5 L8).
- Diego Costa has scored six goals in his last seven Premier League appearances, after netting just three in his previous 14 this season.
- Louis Van Gaal's side mustered seven shots on target - their joint most in a Premier League away game this season (also vs Everton).
- Despite still being unbeaten under Guus Hiddink this season, Chelsea are winless in four consecutive Premier League home games for the first time since November 2012.
- Wayne Rooney has been involved in as many Premier League goals in six games in 2016 (5 goals, 3 assists), as he had in 33 games in 2015 (6 goals, 2 assists).