The last-gasp 2-1 loss at The Hawthorns left the Villa players deflated but Walker, on loan from Tottenham, has urged his team-mates to bounce back.
Walker told the club`s official website: "It was a derby and the boys in the dressing room were hurting on the final whistle. But we've got the game next week now and we have to pick ourselves up for that one."
Walker praised the work done by Baggies boss Roy Hodgson who has transformed the side's fortunes since taking charge.
He added: "They have been so solid since Roy Hodgson has been in charge. We were told that before the game and it showed.
"We have to look forward to next week now. Saturday is a big game. Wigan need to win but we're looking to bounce back with one ourselves. We're determined to get this result out of our system and look forward."
Source: PA
Source: PA