And eight minutes from time, Deane Smalley, on as a substitute, put the result beyond doubt from the penalty spot after he was hauled down by Dons defender Rhys Weston.
The win keeps Oxford unbeaten away from home in the league this season and now at the summit of League Two, with boss Wilder insistent they keep their foot on the gas.
"It is a completely unpredictable league so we just have to make sure we keep our part of the bargain and keep the hammer down," Wilder said.
"Everything about the performance was good out there and the only thing I was unhappy about was the last 10 minutes when we put undue pressure on ourselves by giving the ball away.
"We have worked hard to get top and that is why we are in that position. We are a hard-working side and we were lucky that our defenders kept up their side of the deal.
"You are not going to get anything given to you at Wimbledon and every game against them we have had to work hard and the clean sheet pleases me.
"When you come away from home you need the players to make good decisions. Good players do that and my players did that for us out there."