Walcott delighted with Vermaelen return for Arsenal
Vermaelen played his first full 90 minutes since returning from injury in the 0-0 draw with Marseille.
Walcott said: "It's nice that we're getting a lot of players back to fitness now. Obviously Thomas has been a massive miss and players who have come in have done a fantastic job.
"It just shows how much competition there is in each position and everyone needs to be on their toes, and you are now fighting for your position because it's up for grabs."