James Constable, back in the starting line-up, fired home his 12th goal of the season, after he outmuscled Torquay defender Aaron Downes before rounding goalkeeper Michael Poke in the 50th minute.
Four minutes later Constable's persistence caught Downes out and the centre-back tripped his man to concede a costly penalty which Damian Batt dispatched.
Downes headed in a corner to give Torquay some hope but Oxford repeatedly caught them on the break before Simon Heslop fired the clincher in the fourth minute of stoppage time.
"The players showed what they were are all about," Wilder said. "After we lost 4-0 at home to Rotherham on Tuesday night, there were a lot of disappointed people around the club, and we took a lot of criticism.
We expected to.
"It was a big hit in midweek, so it was a real test for us, of our character. We are a decent side at the moment, and we're in decent form.
"I was a bit disappointed that we weren't in front at half-time. But I sat our two centre-forwards (Constable and Alfie Potter) down at the interval and told them they'd put each other in through really good football and said they'd get more chances as the game opened up in the second half.
"James had missed two chances that he'd expect to put away, so to show the composure he did for both the first two goals is credit to him."