- West Brom 1, Albion 0
Albion only have themselves to blame after a second successive defeat left them looking anxiously over their shoulders on a hugely frustrating afternoon at the Hawthorns.
There was huge controversy when Lewis Dunk's quickly-taken free kick was initially disallowed by referee Lee Mason, allowed then disallowed after VAR official Simon Hooper intervened.
But Albion were their own worst enemies. They missed two penalties with Pascal Gross hitting the bar and Danny Welbeck the post – the first time in Premier League history that a team has twice struck the woodwork from the spot - while Neal Maupay, Aaron Connolly, Joel Veltman and Leo Trossard all wasted gilt-edged chances and West Brom keeper Sam Johnstone made some excellent saves.
Graham Potter's side racked up 20 shots with six on target and had 70% possession but not for the first time this season the most important statistic wasn't in their favour.
Albion lined up with one change to the side beaten by Crystal Palace on Monday, with Connolly coming in for Steven Alzate.
The Irishman began on the left while Leo Trossard setup on the right behind Neal Maupay, with Alexis Mac Allister supporting the striker from a central position.
West Brom began brightly and went ahead in the 11th minute from the third corner they had already won. It was a poor goal from Albion's perspective as defender Kyle Bartley met Conor Gallagher's in-swinging corner inside the six-yard box and headed past Rob Sanchez.
With a third of the pitch in bright sunshine, Albion's keeper had started wearing a cap but after the goal he dispensed with the headwear.
Albion responded and when Connolly's shot from 15 yards took a deflection Johnstone was happy to see it roll a yard wide of his right-hand post. Dan Burn went up for the corner with Okay Yokuslu and Mason initially ignored appeals for handball the West Brom defender before changing his mind after a VAR check. Gross sent Johnstone the wrong way, but his penalty crashed back off the bar.
Diagne glanced his header from Darnell Furlong's cross narrowly wide before Albion were left fuming after a controversy which, even by the standards of VAR, bordered on the farcical. Mac Allister was brought down in the D, referee Lee Mason blew his whistle and Lewis Dunk spotted a gap as Johnstone organised his wall to stroke the free kick into the corner.
Mason blew his whistle before the free-kick was taken but then blew a second time before the ball crossed the line. The goal was chalked off, but Mason changed his mind and awarded it before VAR official Simon Hooper intervened and, after a four-minute delay, a re-take was ordered which Dunk fired straight at Johnstone.
Albion regrouped and had three great chances to equalise in first-half stoppage time. Trossard threaded a pass into space and Connolly's shot produced a one-handed save from Johnstone then Gross cut the ball back to Maupay but he clipped his shot from close range wide. The Frenchman then forced another save from Johnstone but they also needed Sanchez to make a crucial save when Ashley Maitland-Nile got through on goal.
Adam Lallana came on at the break and Albion frustratingly squandered another great chance six minutes after the restart. Maupay forced Johnstone to push out his angled shot but Connolly fired the loose ball over the top from close range.
With an hour gone Danny Welbeck replaced Connolly before Albion created more good openings. Joel Veltman headed Gross' left-wing cross over from close range then Maupay cleverly picked out Trossard in space in the D but his shot was straight at Johnstone.
Albion had another chance from the spot in the 74th minute when Conor Townsend halted Gross' diagonal run with a mis-timed challenge and Mason signalled a second penalty. Welbeck took responsibility this time, but his right-foot effort struck the inside of the left-hand post as Johnstone dived the other way.
The West Brom keeper made another great save to parry Veltman's blast and appeals for another penalty when Veltman went down were ignored.
It's not the first time Albion skipper Dunk has thought on his feet at a free kick. At Anfield last season, Dunk spotted Liverpool keeper Alisson organising his wall and rolled the ball into the corner. Clarification on why Dunk's goal at the Hawthorns was disallowed is expected later from the Premier League but it appears Lee Mason's second whistle came because he spotted that West Brom keeper Sam Johnstone wasn't ready.
Sam Johnstone's 34th minute stop from Lewis Dunk's second free kick was his 100th save in the Premier League this season, with the West Brom shot stopper becoming the first goalkeeper to reach a century this season. He added more saves after the break on what turned out to be yet another frustrating afternoon in front of goal for Albion.
Albion: Sanchez, Veltman, White (Moder 84), Dunk, Burn, Gross, Bissouma, Connolly (Welbeck 61), Mac Allister (Lallana 45), Trossard, Maupay.
Subs not used: Steele, Jahanbakhsh, Alzate, Tau, Propper, Zeqiri.