Reds suffered only their second home League defeat in 13 games to promotion-chasing Wycombe.
The visitors were ruthless from set pieces, scoring three goals through Nathan Tyson, Adebayo Akinfenwa and Sido Jombati to take control.
Karlan Ahearne-Grant had equalised for Reds with seventh goal in eight games in the 34th minute but Jombati’s goal just past the hour punctured hopes of a home fightback.
They were revived late on by Panutche Camara’s close-range strike but Wycombe held on and Reds had defender Mark Connolly sent off in stoppage time for his second bookable offence. He will now miss the next game at home to Cheltenham on Saturday.
Harry Kewell gave Panutche Camara his first League start since November 25 as he made a solitary change to the side that drew 2-2 against Carlisle.
The visitors arrived with the best away record in the league and after Camara had flicked Jimmy Smith’s cross over in the third minute Matt Bloomfield had two decent chances for Wycombe.
Glenn Morris pushed a low drive that was sneaking inside the left-hand post and then Bloomfield fired over from a good position after capitalising on a slip by Mark Connolly.
Reds went behind in the 26th minute. No one picked up Luke O’Nien in space from a corner and when he drilled a low ball into the box Tyson stabbed it home from close range.
But the hosts levelled eight minutes later with a cracking goal. Smith’s flick-on found Ahearne-Grant and his first-time shot from 20 yards surprised Brown as it rattled into the net.
The hosts were now on the front foot but they were rocked by a second Wycombe goal in the 38th minute – from another set piece. Joe Jacobson’s free kick was only cleared as far as Tyson who lifted it back into the six-yard box where Akinfenwa had enough space to direct a firm header past Morris for his 18th goal of the season.
Josh Payne was booked for a heavy challenge on O’Nien in stoppage time and Smith followed him into Mr Horwood’s notebook ten minutes after the break when he handled trying to reach Lewis Young’s far-post cross.
Kicking towards the home fans, Crawley started the second half brightly but on 62 minutes they conceded a third – from another set-piece.
Akinfenwa had space at the far post from a free kick to fire the ball across goal and defender Jombati stabbed it past a helpless Morris from close range to make it 3-1.
Tyson nearly got a fourth in the 71st minute when he beat the offside trap after Akinfenwa had sent him clear only to drag his right-foot shot just past the far post. Then O’Nien forced Morris to turn his volley over the bar at full stretch as the visitors threatened to stretch their advantage.
The game looked all over but seven minutes from time Reds gave themselves hope. Substitute Jordan Roberts stretched Wycombe down the left and his cross was side-footed into the roof of the net by Camara – his first League goal.
It set up a grandstand finish and tempers boiled over in stoppage time. Mark Connolly and O’Nien contested a loose ball on the touchline but referee Horwood judged Connolly’s challenge to be a booking and he was sent off for his second yellow card.
It was an unsatisfactory end to what had been an enthralling game and Reds will need to bounce back quickly at home to Cheltenham on Saturday if they are to revive their play-off hopes.
Reds: Morris; Young, McNerney, Connolly, Evina; Payne, Bulman; Ahearne-Grant, Smith, Boldewijn; Camara.
Attendance: 2133 (459 away)
Man of the match: Dannie Bulman
Pictured: Karlan Ahearne-Grant fires home his seventh goal of the season. Photo by James Boardman of Telephoto Images