Martinez suggested his players had struggled to cope with the demands of their fixture schedule when a Latics side showing just four changes from a midweek Carling Cup tie against Swansea were beaten 2-0 by Mark Hughes' team in October.
Going into Saturday's game at the DW Stadium, though, Wigan will have had a full week without a match for the first time since Boxing Day.
Several regular starters were rested for last weekend's 3-2 FA Cup victory at Hull as well and Martinez hopes to see the benefits when the team take on Fulham.
"The performance against Fulham away was one of the biggest disappointments we have had this season," Martinez said.
"We didn't perform at our level, we were quite flat and probably the cup competition took too much out of our energy tank.
"We need to look at the game on Saturday as a great opportunity to be ourselves and try to put that performance right with the second encounter."
A player who has certainly had a chance to recharge his batteries is Charles N'Zogbia, who returns to the Latics squad after serving a three-match suspension.
Goalkeeper Chris Kirkland missed the Hull game following the bang to the head he suffered in the previous fixture against Bolton and will have his condition assessed.
In other injury news, James McCarthy has targeted the match against Arsenal on January 22 for his potential return to action.
Franco Di Santo (ankle) and Victor Moses (shoulder) are also doing well.
Meanwhile, Hughes has boldly declared Fulham's slump over as he looks to mastermind a fourth win in five games.
The Cottagers found themselves sucked into a Barclays Premier League relegation dogfight towards the end of 2010 after winning just two of their opening 18 games.
But they have doubled that tally in their last three league matches to climb out of the drop zone and are also through to the fourth round of the FA Cup after thumping Peterborough 6-2 last weekend.
Hughes said: "At the moment, we're getting results and we're pleased with that.
"That's three wins in four games.
"I think we're in good shape.
"We're enjoying our football at the moment, playing some good stuff, scoring goals - thankfully - now and we're getting players back as well.
"We look in better shape than we were just prior to the Christmas period."
Hughes' poor start to life at Craven Cottage piled the pressure on the former Manchester City boss, who had to endure taunts from his own fans following the Boxing Day defeat to West Ham.
He said of the run: "I'd rather go through that at the beginning of the season than the second half when it's the business end.
"You've got to be moving forward at the crucial end of the season.
"You've got to be really strong in the second half and I'm confident that we'll be fine.
"In the second half of the season, my teams are always stronger."
Fulham find themselves just a point outside the bottom three, despite losing only seven of their 21 league games - proof of how damaging draws can be.
"Draws don't really push you up the league, so we're looking for positive three-point wins if we can," said Hughes.
"Because that's what moves you up the league, that's what consolidates your position."
Source: DSG
