These two sides continued their unbeaten start to the season in a contest which was not lacking in controversy and which ended in a 1-1 draw.
Northampton's Fred Murray was given his marching orders by referee Carl Boyeson in the 59th minute for a trip on Wycombe striker Nathan Tyson, who appeared to half give his challenger the slip before being caught.
But Northampton, who failed to register a shot of any description during the first half, were lifted by the dismissal and could have snatched an unlikely victory.
Tyson continually gave the home defence the run around but it was skipper Keith Ryan who was close to opening the scoring in the fourth minute with a 25-yard screamer that flew just wide.
Ian Stonebridge tested Lee Harper with a first-time shot on the turn after quarter of an hour and it was the former Plymouth striker who knocked his first goal for the Chairboys three minutes before the break after a flowing move by the visitors.
Gary Silk sent Tyson away down the left and he cut in behind the home defence before delivering a low cross which Stonebridge converted.
But the home side stunned Wycombe less then 40 seconds after the restart when Scott McGleish threaded a pass for Marc Richards and the striker beat Frank Talia as he advanced from his goal.
Murray's dismissal ensured the game's tempo went up a notch and David Galbraith squandered a glorious chance to give the Cobblers a lead in the 65th minute when he spooned a shot over the bar from 15 yards.
At the other end, Stonebridge was put through by Tyson but Harper made a sharp point-blank save. Then the tricky Eric Sabin teed-up Richards only for the striker to curl a shot onto the crossbar before Joshua Low picked up the rebound, only to fire inches wide.
But it was Tyson who almost had the last laugh 11 minutes from time but his angled shot went just wide.