The English striker netted his fourth goal of the season to book Arsenal’s spot in the semi-final of the EFL Cup.
However, the victory did come at some cost as fellow striker Olivier Giroud picked up a hamstring injury which rules him out of Friday’s clash with Liverpool (7.45pm).
Welbeck has been on the fringes of the first team this season and he made his 10th start of the campaign last night.
But now he will be hoping he jumps up the pecking order given Giroud’s absence – and Wenger was impressed with how he played against the Hammers.
“He scored and that will be good for him,” Wenger said.
“He lasted 90 minutes and that’s a positive.
Wenger was also impressed with how his team performed given he made 11 changes from the victory over Newcastle at the weekend.
“I felt we played with quality and spirt and pace in the first half,” Wenger added.
“For 90 minutes we looked solid defensively.
“Second half we lost a bit of pace and were less creative. So it was down to not making a mistake.
“Overall it’s a positive night, other than we lost Olivier Giroud.”
Arsenal will find out who their semi-final opponent is when the draw is made after the conclusion of Bristol City vs Manchester United tonight (8pm).