A goalless opening 45 minutes gave little indication of what was to come as a spectacular overhead kick from Rod McDonald set Northampton on their way to a memorable away victory at a side who themselves harbour promotion aspirations.
Ricky Holmes doubled the lead with another fabulous goal 10 minutes later before James Collins struck twice late on to put the seal on a resounding win.
“I thought we really looked a proper side second half,” said Wilder afterwards.
“That was a tough game today. I said that before the game with the players they have to choose from and their results they’ve had.
“There was nothing in the game first half. We had to endure a little bit of pressure and we possibly had the best chance but it was a scrappy game.
“I didn’t think we played very well first half but sometimes you need a little bit of magic to get you going and I thought that we were comfortable winners after Rod produced the goal.
“We played like a side that really believed in themselves and drove the game forward and then we scored another fantastic goal through Ricky before adding two late on.
“It’s a good afternoon for us.”
Asked if he felt this was his side’s most complete performance of the season, Wilder added: “Obviously we scored four goals and kept a clean sheet but we weren’t at our best first half and goals change games and the quality of our goals were outstanding.
“It’s a nine-month season, a 46-game season and sometimes you’re not at your best.
“We countered three or four times and took the wrong options and we had the unfortunate situation of losing Joel Byrom which unsettled us a little bit.
“I didn’t think our quality at the top of the pitch was great first half but we’ve got the likes of Ricky, Lee Martin and Lawson (D’Ath) coming on and we’ve got goals at the top of the pitch.
“We showed that second half and we looked a proper team. It looks a really comfortable win but we’ve had to work hard.”
On McDonald’s goal, Wilder continued: “We were right behind it and as soon as the ball left his foot we knew it was in. Sometimes you need that little bit of magic or something to get you going.”
Wilder also confirmed that Byrom “cricked” his neck in the warm-up.