Garcia's side earned their third straight victory and ended the Latics unbeaten home record this season.
“I am very pleased and very proud of my players because all of them gave 100% and, if you don’t work hard, it is impossible to win here," said Garcia.
“I’m very pleased because no (visiting) team had won here. To be the first to do it is an honour for us.
“We had some good chances to score, they had one or two. We took our chance and that made the difference.”
The win saw Brighton leapfrog the Latics in the table and move up to ninth.