The Latics had looked the most likely of the bottom three to climb out of the relegation zone after a promising run of results that included draws with Liverpool and Chelsea but they failed to capitalise on early dominance and slumped to a 4-1 defeat.
It was Wigan's fifth match in just over a fortnight, but Sunderland were arguably in a worse position having run themselves into the ground beating leaders Manchester City on Sunday while also having to contend with a lengthy injury list.
Martinez believes the contrasting styles of play of the two sides played into the visitors' hands, though, with Wigan making most of the running.
The Spaniard tried to freshen things up by resting Victor Moses and Mohamed Diame but a first-half injury to Albert Crusat meant Moses ended up playing more than 50 minutes.
Martinez said: "If I could have made 10 changes I would have made 10 changes.
"We played against Stoke with 10 men for 20 minutes and the games we had previously here took a lot out of the players. It was a game too many.
"And I know it sounds a bit ridiculous when we know Sunderland played 48 hours before but the two roles out there were very different.
"Probably playing 48 hours earlier for Sunderland was a real help because they had a reason to sit back, defend and allow us to have the ball and you need real energy to break a team down.
"Albert Crusat has been working really well and he brought us fresh legs. When Victor came on and Momo came on we were a little bit tired and that affects your play, you become a little bit pedestrian.
"The hardest thing in football is to score from open play when the opposition has 11 players behind the ball, and we had that role. It's something we need to learn in the future that we should be capable of winning games when that happens.
"It's been a very tough period in terms of fixtures in December and over the festive period and I just feel we need a break.
"We need to refresh, concentrate on the FA Cup and make sure we are strong and ready for the Queen's Park Rangers game."
The result continued the superb start to life as Sunderland boss for Martin O'Neill, making it four wins, a draw and only one defeat from his six games in charge.
The Northern Irishman's biggest challenge now may be keeping expectations in check at the Stadium of Light, and he insisted they are not yet out of the woods in terms of the relegation shake-up despite climbing to 10th.
He said: "The positions in the table don't concern me, it's the points on the board that are the most important thing. To win gives us a second or two of breathing space, and that's what it is.
"We've got some tough matches still coming up in January, important games for us. To take a break from the Premier League with that win gives us a bit more confidence."
Injuries are certainly O'Neill's biggest problem at the moment, with Lee Cattermole and Jack Colback both in the wars on Tuesday night while goalkeeper Simon Mignolet is playing in a face mask.
The situation could force O'Neill's hand in the transfer window, but he said: "I'll speak to the owner in the next couple of days and we'll have a look at it.
"I'll just reiterate, I didn't take this job on the promise of money available in January. The injuries will cause us a problem because when it gets to February 1 that's all you can do, that's it for the season."