West Brom's Premiership survival hopes suffered a setback as they lost at home to Arsenal, who in turn kept themselves in pole position for second place.
Robin van Persie grabbed the first goal, taking Jose Reyes' pass and slotting coolly past Russell Hoult.
Substitute Edu hit the second to break West Brom hearts after Dennis Bergkamp had played him in in stoppage time.
The Baggies dominated for long spells but failed to create many clear-cut chances against the former champions.
But, although the Gunners had the better chances, West Brom will feel aggrieved they took nothing from the game and now face Manchester United and Portsmouth as they bid to stay in the league.
The Baggies knew a win would take them out of the drop zone and they came flying out of the blocks, with the impressive Kieran Richardson at the heart of their forward momentum.
An early in-swinging Richardson corner was not cleared by Arsenal and it dropped to Zoltan Gera, who produced an acrobatic overhead kick only to send the ball wide.
The Baggies were not ripping through the Gunners defence at will - Philippe Senderos and Kolo Toure made sure of that - but they were causing problems with their movement and Kevin Campbell's link-up play was proving effective.
In contrast the high tempo Arsenal usually play at was missing and they only sparked into life near the end of the half, Van Persie forcing a fine save from Hoult as Lauren's pass carved West Brom's defence open.
If Bryan Robson asked his team to show the same workrate and determination after the interval he would have been delighted with his players' response.
The capacity-crowd at The Hawthorns were in full voice and with Arsenal below-par they sensed a chance to see their side pull off a famous, and crucial, victory.
Gunners' strike pair Reyes and Van Persie had barely threatened as Darren Moore and Thomas Gaardsoe worked hard to keep them at bay, but halfway through the half their class finally told.
Reyes found space on the edge of the West Brom box and his crisp pass enabled Van Persie to work an opening and slot clinically past Hoult with his left foot from 14 yards.
Moments later the revitalised Reyes took Van Persie's pass and went on a mazy run only to see his shot cleared off the line by Neil Clement.
The Baggies responded with Richardson foiled from 25 yards by Lehmann, before Robson decided to go for broke by bringing on three strikers in Kanu, Rob Earnshaw and Geoff Horsfield.
But they could find no way through and Arsenal closed out the contest with Edu collecting Bergkamp's pass and lifting the ball into the net via Hoult's shoulder.
West Brom: Hoult, Gaardsoe, Moore, Clement, Albrechtsen (Earnshaw 80), Wallwork, Richardson, Robinson, Gera (Kanu 80), Campbell (Horsfield 80), Greening.
Subs Not Used: Scimeca, Kuszczak.
Arsenal: Lehmann, Lauren, Toure, Senderos, Cole, Fabregas (Bergkamp 74), Vieira, Silva, Pires, Van Persie (Edu 74), Reyes.
Subs Not Used: Campbell, Almunia, Aliadiere.
Goals: Van Persie 66, Edu 90.
Ref: N Barry (N Lincolnshire).