But as this game looked to be petering out to a goalless draw and yet another indication that the Gunners lack the credentials to be serious title challengers, up popped Olivier Giroud with just four minutes left.
Handed his first Premier League start of the season by Arsene Wenger, the France international rose with the sort of grace that belied a game that proved more testing than it should have if those title chances are to be in any way realistic.
Mesut Ozil, a lightning rod for criticism in recent weeks, supplied the perfect cross for Giroud to outmuscle Gareth McAuley and loop his header over Ben Foster and into the net.
It was cruel on Foster, whose string of magnificent saves during the second half onslaught kept the Baggies in with a chance of stealing a point.
A wonderful tip over from Alexis Sanchez’s blistering strike was the best of the lot as frustration grew.
If Foster’s one-man mission to keep the Gunners out was West Brom’s highlight then Arsenal constantly looked to prize-asset Sanchez.
Ever willing, the former Barcelona man was once again their brightest spark, a constant pain the backside.
The closest Sanchez and Arsenal came to breaking the deadlock before the winner came when the tricky winger struck the post after weaving himself into space inside the penalty area.
Claudio Yacob then spurned a guilt-edge chance to condemn the Gunners to more misery, blasting over from just five yards out after Petr Cech spilled under pressure.
The Baggies were pinned up against the ropes with the Gunners in desperate search of that critical knockout blow. And it was left to Giroud to rise highest and restore smiles to faces in north London following consecutive defeats at Everton and title rivals Manchester City.
Wenger had cut an increasingly frustrated figure until his compatriot saved the day, and he was quick to compliment the 30-year-old’s qualities.
“He always makes a point.” Wenger said. “He’s scored many times when he’s come on and he has qualities in our squad that are needed that many of the other players have not.
“He’s a fighter Olivier, he has a fantastic mentality.”
While the overall display was unconvincing, Wenger hopes a much-needed three points will restore some momentum and confidence to a campaign that looked in danger of swerving off the rails altogether had West Brom hung on.
“The confidence is swinging,” Wenger admitted. “We have played 20 games, 14 games in the Premier League and six games in the Champions League without losing a game and then we lost two on the trot, so the confidence was hit.
“It’s a good test. There is no season without disappointment and it’s always interesting to see how the team responds to disappointment.”
West Brom have enjoyed a remarkable turnaround under Tony Pulis, whose enigmatic approach and keen eye for detail have rubbed off on his players.
The Baggies boss believes his side have what it takes to compete with the top sides in the league but need to summon greater consistency if they are to reach new heights.
“We’ve come up against a very good side with top players,” Pulis said. “We’ve worked hard on the system and I’m desperately disappointed for the players and supporters who have travelled.
“It’s a little bit ‘deja vu’ with the Chelsea game. Gareth’s got pinned by Giroud and you can’t allow him to do that because he is such a strong player and he’s excellent in the air.”
Pulis suffered in a similar vein at Chelsea in the Baggies’ last away league game and he admits one lapse of concentration can be enough against the top sides.
“I don’t think you can ever switch off,” Pulis said. “And that’s been proved against the two teams we’ve lost to recently. You have to concentrate for as long as it takes because the top teams win so many games in the last 10 minutes. They are relentless in the way they play and the top six teams will win a lot of games in that way.”
Cech 6; Bellerin 7, Gabriel 6, Koscielny 7, Gibbs 6 (Monreal 71 6); Coquelin 6 (Ramsey 74 6), Xhaka 7; Sanchez 8, Ozil 6, Iwobi 7 (Perez 71 6); Giroud 6.
Ospina, Holding, Reine-Adelaide, Elneny.
Foster 8; Dawson 7, McAuley 7, Evans 7, Nyom 7; Yacob 7, Fletcher 7; Brunt 6, Chadli 6 (McClean 62 6), Phillips 6; Rondon 7 (Robson-Kanu 80 5).
Myhill, Olsson, Morrison, Gardner, Galloway.