West Brom 0-2 Arsenal
Goals from Nwankwo Kanu and Jeremie Aliadiere sent Arsenal into the Carling Cup semi-finals as Arsene Wenger's side edged out West Brom at The Hawthorns.
Kanu scored his second goal of the season
Russell Hoult saved Kanu's headed effort on 25 minutes, but was powerless to stop the Nigerian's follow-up.
Arsenal wrapped the game up in the 57th minute when Hoult's poor clearance went to Aliadiere, who easily scored.
West Brom created chances, but their finishing lacked Arsenal's precision.
Throughout the game Gary Megson's side carved out a succession of openings as Arsenal struggled to deal with their strength and enthusiasm.
Just before Aliadiere's goal, Lee Hughes missed one of West Brom's better chances when he blasted his shot over the bar with just Graham Stack to beat.
Stack had a busy first-half as West Brom bombarded his goal with a succession of high balls from crosses and set-pieces.
He fumbled Neil Clement's free-kick but then grew in confidence once he had come out bravely and quickly to save from Scott Dobie.
Clement then scampered down the left wing and delivered a dipping cross which clipped the bar.
West Brom's aerial assault caused Martin Keown particular problems, and a couple of his rugged challenges on Dobie and Andy Johnson might easily have seen the Arsenal defender punished by another referee.
Johnson was then felled by Efstathios Tavlaridis and soon after had to limp off.
Amid all this West Brom pressure Arsenal took the lead on 25 minutes.
Lauren's deflected cross reached Kanu, whose first headed effort was saved by Hoult, before the Nigerian reacted quickly to force home the rebound.
The second-half's start was delayed due to an injury to the fourth official and required Dermot Gallagher, who was watching in the stands, to step in.
25 mins: Kanu gives Arsenal the lead against the run of play
57 mins: Aliadiere makes the game safe for Arsenal
84 mins: Dobie hits the bar for West Brom
Once the second-half got underway Stack came under renewed pressure, saving bravely from Rob Hulse.
Hughes then evaded the Arsenal offside trap but rushed his effort, blasting over the bar.
On 57 minutes Aliadiere showed no such lack of composure when Hoult disastrously cleared Thomas Gaardsoe's backpass straight to the Arsenal striker.
The young Frenchman quickly gathered the ball and nonchalantly placed it in the net to give Arsenal a two-goal cushion.
West Brom never gave up and Dobie hit the bar, while Hughes went close again.
West Brom: Hoult, Gregan, Gaardsoe, Volmer (Gilchrist 65),
Haas, O'Connor (Sakiri 71), Wallwork, Johnson (Hughes 39),
Clement, Hulse, Dobie.
Subs not used: Murphy, James Chambers.
Arsenal: Stack, Lauren, Keown, Tavlaridis, Clichy, Wiltord,
Parlour, Edu, Bentley (Thomas 81),
Aliadiere (Fabregas Soler 73), Kanu.
Subs not used: Shaaban, Papadopulos, Simek.
Referee: M Messias (N Yorkshire).