Wycombe suffered a heavy 5-1 defeat to Bristol Rovers in the opening group stage match of the Checkatrade Trophy at Adams Park.
Dayle Southwell's early strike proved to be a false dawn as the Pirates came roaring back with goals from Dom Telford (two), Ryan Broom (two) and Liam Sercombe.
Gareth Ainsworth made six changes to the side that won 3-2 at Grimsby at the weekend, with Sido Jombati, Jack Williams, Marcus Bean, Dayle Southwell and Nick Freeman coming into the side, with new signing Josh Umerah making his debut leading the Chairboys attack.
Wycombe began the game on the front foot and took the lead inside the first four minutes. Freeman played a deep corner which was headed back across goal by Bean and Southwell was there to nod home for his first of the season.
Freeman and Southwell almost combined again four minutes later as the winger used good trickery to gain a yard of space before whipping in a low cross which just evaded Dayle in the box.
Bristol Rovers levelled the scores on nine minutes as Telford forced his way through and tucked it away with aplomb.
Wanderers continued with some confident passing moves. Michael Harriman's low cross was almost turned into his own net by Tom Broadbent, but Jonny Burn was there to save his blushes just before the half-hour mark.
Wanderers had another great chance to retake the lead as Dominic Gape was played through, Sam Slocombe denied the midfielder before the ball dropped loose to Umerah who's effort was deflected wide.
Ainsworth's side were made to pay for not taking advantage of their dominance as Rovers clincally turned the game on its head as Telford got his second on 42 minutes as he headed in.
Half-time: Wycombe 1-2 Bristol Rovers
Rovers came flying out the traps in the second half, leaving the Chairboys cold. Rory Gaffney sent a warning sign as he was twice denied in the early stages of the restart.
The Gas doubled their advantage as Broom tapped home a tidy move from the visitors on 54 minutes.
The Chairboys went close to cutting the defecit; firstly Jombati headed wide from a corner and then Southwell missed a one-on-one after being played in by Luke O'Nien.
The game was pretty much put to bed on 63 minutes as Sercombe hit one from 30-yards, beating Scott Brown all ends up.
Umerah, who had made bright start to life at Adams Park, was denied a debut goal by the assistant's flag on 74 minutes, as he bundled home substitute Anthony Stewart's header from a corner.
Late chances from an O'Nien free kick and a Freeman shot from just outside the box came to nothing, and there was to be a late blow as Broom scored an almost identical goal to his first from a Telford low-ball.
A humbling defeat for Wanderers who now look to pick themselves up ahead of the visit of Forest Green Rovers in Sky Bet League Two this weekend.
50/50 Result: £1 Draw (186.50) - 04733