Welbeck who will be out of contract next summer, is yet to start a league game this season, but now has four goals to his name for Arsenal.
A fine Alan Judge free-kick halved the arrears but, despite Brentford outplaying their hosts for much of the second half, substitute Alexandre Lacazette wrapped up the win in stoppage time. "He gives us his quality and commitment every day", the Arsenal boss told his post-match press conference.
"I want to look at him also with our best performance and for him to stay in first XI".
He added: "For Saturday [against Watford] he is another player I can try to help in the first XI". I said to the players at half-time, "We can either sit behind the ball and let Arsenal have it and take 2-0, or go and ask a question".