Nicky Bailey's 76th minute strike settled a largely even affair in Charlton Athletic's favour as the Wanderers succumbed to a narrow 2-1 defeat at Adams Park.
The third-placed side took the lead inside 11 minutes when Jonjo Shelvey found the net from the edge of the area, but the Blues showed the same battling qualities that had earned them a point at Leeds United the previous week, and grabbed a deserved equaliser through Jon-Paul Pittman on 64 minutes.
Pittman, who had grabbed the headlines with his leveller at Elland Road, finished expertly from just inside the box to restore parity but the Addicks stepped up a gear and claimed all three points when the excellent Bailey fired home at the near post.
Gary Waddock's Wycombe side were unable to conjure up a second equaliser despite a late rally and remain in 23rd position in League One.
The Blues boss made one change from Saturday's 1-1 draw at Leeds United, with Stuart Green replacing the departed Tommy Doherty in midfield.
Buoyed by their display at Elland Road, the Blues began on the frontfoot and should have been ahead as early as the sixth minute. Stuart Beavon ran the length of the Charlton half, skipping away from numerous challenges on his mazy run but, when confronted by Addicks keeper Rob Elliot, he stroked the ball wide of the left post from 12 yards.
The in-form Pittman then sent a strike wide of the Addicks' goal after a nicely waited pass down the right channel by Scott Davies.
Charlton responded, and the visitors thought they had taken the lead on 10 minutes when Deon Burton found the bottom corner, but he was adjudged to have been in an offside position.
However, they only had to wait another minute before they did make it 1-0. Nicky Bailey's cross from the left was turned into the path of Jonjo Shelvey by Lloyd Sam and the midfielder fired past Scott Shearer on 11 minutes to hand the Addicks the early advantage.
On Reading striker David Mooney forced Shearer into a good save two minutes later, while at the other end Matt Harrold headed wide a Lewis Hunt cross under pressure from Charlton centre-back Miguel Llera.
Hunt himself then flashed a shot just over Elliot's top right corner from 25 yards after going on a jinking run which began in the Wanderers' half.
Charlton began to grow in stature and both Bailey and Burton went close within a five-minute spell. Firstly, the Addicks skipper curled an effort over the bar from 20 yards before Burton couldn't quite direct his header on target after a good cross from Grant Basey.
Burton went close again moments later, this time testing Shearer from the edge of the Blues' 18-yard box after a ball across the box from strike partner Mooney.
Waddock's Wanderers rallied at the end of the half but the former Premier League side held firm and went in 1-0 up at the break.
The wet conditions were making it difficult for either side to play their usual passing game and that forced a drop in tempo at the beginning of the second period.
However, a mistake from skipper Craig Woodman allowed Mooney to be played in down the right but Shearer was up to the task, pushing the Reading loanee's effort round the round the post.
The Blues battled back, and only a last-ditch challenge from Llera inside the six-yard box denied Matt Harrold an equaliser on the hour mark, after nice play from Stuart Green, Beavon and Woodman.
However, the home side's growing pressure finally told on 64 minutes when Pittman slammed home his ninth of the season and second in two games to draw the Blues level. Green's pull back was seized upon by JP, who allowed the ball to roll onto his left foot before striking past Elliot from 12 yards.
Sensing a winner, Waddock replaced Beavon and Green with Matt Phillips and Kevin Betsy. And Phillips nearly made an immediate impact, firing just wide of the Charlton goal after a nice flick-on by Harrold.
But it was Phil Parkinson's men who would have the last laugh. The Blues failed to clear their lines and, after Shearer had saved magnificently from Shelvey's close range effort, Bailey seized on the loose ball to smash home on 76 minutes at the second attempt.
The Chairboys drove forward in search of an equaliser and both Chris Westwood and Matty Phillips had chances in the closing stages, but Charlton held on to claim all three points.