Distributed the ball effectively and dealt with several shots that were peppered in on his goal. Could do little about either of the Arsenal goals.
Was caught napping for the opening goal but was always on hand to deal with the intricate play the Gunners attempted through the heart of the hosts' defence.
Was troubled throughout by Giroud's willingness in the air but dealt with the threat well. Got caught out of position for Rosicky's second of the afternoon.
Was given a tough test as Gervinho and Sagna doubled up on him down the Gunners' right-hand side and was not offered much help from Thomas in front of him.
Marauding runs down the right aside, the right-back found several of Arsenal's attacks too quick, with Monreal eager to overlap the ever-changing partner down the left.
Wasteful in possession and often guilty of not tracking his runners as Cazorla and Rosicky found pockets of space to work in.
Anonymous throughout and did little to help his side regain any momentum down the right-hand side. Failed to track the impressive Monreal.
Was overrun in midfield by the creative trio of Arteta, Rosicky and Cazorla but fought valiantly to get his team back in the match. Kept a cool head to tuck home a spot-kick to get the Baggies back in contention.
Failed to get the better of Sagna, and when he did, he was unable to take advantage and provide the service Long craved.
Tidy in midfield but lacked an end product in the final third as Arsenal dominated proceedings in the middle of the pitch.
Caught offside numerous times and was unable to get the better of Koscielny and Mertesacker in a frustrating afternoon for the Irish forward. Got the reward his tireless running deserved when he won the penalty.
A tidy display from the Pole, whose distribution was consistent and made the necessary stops when required to do so.
A largely solid display from the German, who dealt well with the direct balls the Baggies launched at the Gunners until he brought down Long. The pace of the game caught up with him and his red card left his side clinging on in the closing exchanges.
Provided an attacking outlet but his crossing was often wayward but stuck to his defensive duties throughout and snuffed out the threat of Thomas.
Another solid display from the ever-improving Spaniard, who didn't' allow Dorrans a chance to run at him and got forward effectively too.
Marshalled the defence superbly and was always on hand to mop up behind Mertesacker. Caught Long offside several times as Arsenal's defensive line held well.
His typical tidy self, pulling the strings for the Gunners in midfield and winning a number of free kicks for his side when they had to hold on.
Brilliant performance from a player often criticised by Gunners fans. Set the tempo in midfield although his passing often let him down in the final third. Missed a great chance to double the lead in first half but provided the assist for Rosicky's second.
Was the difference between the two teams. Took his goals superbly and was a constant thorn in the Baggies' defence as he probed for a decisive through-ball. Even threw in a goal-line clearance in the opening period for good measure.
Started off his frustrating self but slowly grew into the game. Set up the goal brilliantly after twisting Jones before firing in superb cross for Rosicky.
Provided a physical figure up front and some of his link-up play was exemplary at times but faded badly in the second half and was guilty of not closing down.