Two goals in two minutes from Arouna Kone put the Latics ahead before half-time, with Maynor Figueroa adding a third three minutes into the second half.
Reading striker Pavel Pogrebnyak was sent off with 35 minutes remaining, and with Aston Villa losing at Arsenal, Wigan moved out of the bottom three in the Premier League at the final whistle.
"Delighted is the best word to describe it," Martinez declared. "We knew how hard it was going to be with the recent results Reading had, and we never underestimated how difficult a task it was going to be.
"I'm so pleased to keep a clean sheet today. To keep out Reading with no shots on target was an incredible effort from all the players, and showed how well they were drilled and focused in their defensive job.
"On top of that we were able to play like ourselves, and be ourselves. To score the goals in the manner that we did is very pleasing.
"It was a complete performance in a very difficult environment, at a difficult moment of the season, it was very pleasing for us."
The win was Wigan's first in the league in eight attempts since beating Villa in late December, but the Uruguayan feels this season's battle to avoid relegation will be more difficult than previous successful efforts.
"We want to be as consistent as we can until the end of the season, show the same standards that we did today. We need to carry on this mentality and this focus, but it is going to be a close, close fight until the final day of the season. It is probably the hardest of all, because of the quality of the teams around us."