EPL: Southampton 2-3 Chelsea
Olivier Giroud celebrates scoring their third goal
Olivier Giroud came off the bench to score twice as Chelsea came from two goals down to beat struggling Southampton 3-2 and keep alive their hopes of Champions League qualification.
The home team went ahead thanks to Dusan Tadic's fourth Premier League goal of the season (21), before Jan Bednarek volleyed home a second on his top-flight debut (60).
However, the champions responded in style by scoring three times in only eight minutes, the first a stooping header by substitute Giroud (70), before Eden Hazard's composed finish brought them level (75).
Then with 12 minutes to go Giroud completed the comeback with a low drive to inflict a fourth defeat in a row on the struggling Saints.
As a result, Southampton remain in the relegation zone, while Antonio Conte's team, after their first two-goal comeback since 2002, moved to within seven points of both Tottenham and Liverpool - who play later today - in the race for the top four.
Southampton had opened the scoring after 21 largely uneventful minutes following a lovely build-up down their left flank involving Ryan Bertrand, sent clear by Pierre-Emile Hojbjerg's inch-perfect pass.
The England left-back then got the better of Cesar Azpilicueta in a foot race, before pulling the ball back for the waiting Tadic to nip in front of his marker and poke the hosts ahead with his first strike since Boxing Day.
It took a flat Chelsea - fortunate not to see Marcos Alonso sent off for a late tackle on Shane Long just before the break - until the second half to test Alex McCarthy.
The Saints No 1 just did enough though to keep out Willian's low drive from the edge of the area, minutes after Thibaut Courtois also had to be alert to touch over Long's looping effort.
However, Mark Hughes - taking charge of Southampton at St Mary's for the first time - only had to wait till the hour-mark for his side to double their lead, and it came via an unlikely source.
James Ward-Prowse floated a free kick to the far post for Bednarek to cushion a volley past Courtois as a first league win under their new manager appeared to be on the cards, only for the visitors to hit back with three goals in only eight minutes.
Chelsea, meanwhile, made two alterations from last weekend's 1-1 home draw against West Ham, with Andreas Christensen and Davide Zappacosta coming in for Antonio Rudiger and Victor Moses, with the German not even in the Blues squad.
Giroud, only just off the bench, headed in Alonso's inch-perfect cross from the left, before Hazard kept his cool to trap Willian's cut back and drill the Blues level as Southampton heads dropped.
And the France international then sealed a quite remarkable turnaround by firing through a posse of Saints defenders to keep Chelsea's Champions League hopes alive.