London - Diego Costa snaffled a stoppage-time equaliser to preserve interim manager Guus Hiddink's unbeaten record as Chelsea snatched a 1-1 draw at home to Manchester United on Sunday.
United looked to be closing to within four points of the Premier League's top four after Jesse Lingard's 61st-minute goal set Louis van Gaal's men on course for a third consecutive win in all competitions.
But in the first of six minutes of injury time, added on for a serious-looking knee injury to Chelsea centre-back Kurt Zouma, Costa rounded David de Gea to score, extending Hiddink's unbeaten run since succeeding the sacked Jose Mourinho to 10 matches.
Chelsea remain 13th, 17 points below the top four, but while their Champions League qualification hopes have long seemed over, Costa's goal dealt a weighty blow to embattled United manager Van Gaal.
Van Gaal bullishly dismissed speculation linking Mourinho with his job prior to the game, but finishes the weekend with his side six points below the top four.
Buoyed by breezy recent wins over Derby County, in the FA Cup, and Stoke City, in the league, United had made a strong start, with Anthony Martial testing Thibaut Courtois in the 18th minute.
Chelsea rallied, John Terry seeing a penalty appeal waved away after his shot hit Daley Blind on the arm, but after Zouma had been carried off following an awkward fall, United made the breakthrough.
Cameron Borthwick-Jackson's cross was helped on by Wayne Rooney and Lingard took a touch before slamming in his second goal in two games.
But after United goalkeeper De Gea had saved from Branislav Ivanovic and Cesc Fabregas, Costa equalised in stoppage time when he gathered Fabregas's pass, rounded De Gea and slotted home.