- Southampton 1, Albion 2
Albion gave themselves precious breathing space at the bottom of the table with a crucial win at St Mary's.
Skipper Lewis Dunk's fourth goal of the season put his side in front before Che Adams levelled, but Albion were back in front 11 minutes after the break when Leandro Trossard finished off a superb move to score his third of the campaign.
Southampton pushed for an equaliser and Rob Sanchez made a crucial save to deny Adams, but a fifth away win of the season means Albion climb to 16th, three points clear of the relegation places, with a crucial home game against Newcastle to come on Saturday.
Danny Welbeck returned to the side in the one change made by Graham Potter with Alexis Mac Allister on the bench. Adam Lallana took up a deeper role central of a three-man midfield with Pascal Gross on the right and Yves Bissouma on the left. With Dan Burn pushing onto Kyle Walker-Peters, as Albion looked to exploit his height advantage, there was an onus on Trossard to help defensively in the first half.
The Belgian had two efforts at goal in the fifth minute after Lallana picked him out but his first shot was inadvertently blocked by Welbeck and the follow-up cannoned off Jannik Vestergaard but by then the flag was up for offside against Neal Maupay.
Albion had made a strong start though and it was rewarded in the 16th minute. Fraser Forster was forced to push Maupay's shot away at full stretch but from Gross' corner on the right Dunk found space around the penalty spot to power a header inside Forster’s left-hand post.
Once again though Albion surrendered the lead with Adams equalising 11 minutes later. Dunk tried to head away Ryan Bertrand's cross but only succeeded in flicking it to Adams, who volleyed powerfully past Sanchez from close range.
Albion should have restored their lead three minutes before the break. Welbeck and Burn combined before the defender rolled a pass into the path of Gross on the right, but the German shot straight at Forster, who blocked it with his right leg, when a strike either side of him would have resulted in a goal. In stoppage time the Saints keeper was involved again, this time to make a more routine stop from Trossard's left-foot volley.
Albion were forced into a change at half-time with Andi Zeqiri replacing Burn, who appeared to have tweaked his hamstring. Sanchez made the first save of the second period when he got down to hold James Ward-Prowse's volley but it was Albion who regained the advantage with a superb 56th-minute goal. Lallana's pass found Welbeck whose perfectly-weighted lay-off allowed Trossard to advance into the box without breaking stride and lash the ball high past Forster.
Albion's defensive wall did its job when Gross deflected Ward-Prowse's free kick from a central position on the edge of the box moments after Sanchez superbly saved from Adams. As the game opened up again, Zeqiri drove a powerful cross-shot from wide on the left that only needed a touch and Albion would have had a third. Gross then tried to surprise Forster by drilling a free-kick from the left-hand corner of the box under the wall which took a deflection and the keeper was able to make the save.
Davy Propper replaced Welbeck for the last 13 minutes to strengthen midfield with Trossard pushing on in support of Maupay. Trossard was then replaced by Jakub Moder with five minutes remaining.
Albion saw out the closing stages relatively comfortably as a weary-looking home side struggled to find a way through and Potter had made a satisfying winning return to one of his former clubs.
His fourth goal of the season was also Lewis Dunk's 20th in the league for Albion and its source was no surprise as 15 of them have come from headers.
Something had to give when the sides with the two worst records at holding a lead came together. Southampton have dropped 18 points from winning positions, Albion 17 while in 12 games when they have gone behind Southampton have only won once – at the Amex in December. This time Albion regained the lead and got the job done.
Albion: Sanchez, Veltman, Dunk, White, Burn (Zeqiri 45), Gross, Bissouma, Lallana, Trossard (Moder 85), Welbeck (Propper 77), Maupay.
Subs not used: Steele, Mac Allister, Moder, Jahanbakhsh, Alzate, Izquierdo, Tau..
Referee: Stuart Attwell