Spanish manager 'delighted' with three points after Franco Di Santo's strike handed his team a 2-1 win that puts them two points above Blackburn in the Premier League
Franco Di Santo grabbed the decisive goal in the dying minutes as the Latics pulled themselves off the bottom of the Premier League table with only their second win of the season.
"I’m delighted with the result," Martinez told reporters after the match. "That is a great example of why we are so hooked on football.
"The contrast of emotions with last week when we drew with Blackburn is massive because we were on the floor and feeling as bad as you can feel but now we are really delighted. We feel just the opposite to last week.
"It was a very close game. Sunderland started with great intensity and we were second best in the opening 20 minutes. There was a lot of long play and we couldn’t adapt to it.
"Ali Al-Habsi was disappointed with the first goal but then he kept us in the game and after that we controlled the game.
"We finished the first half strongly and then we kept a clean sheet [in the second half] through sheer desire and doing the things we normally find difficult and at the end we got the rewards from pressing so far up in a very important game.
"The way we have played makes me feel extremely proud and we are maturing so much. Everyone should be very proud of themselves."
Martinez went on to reiterate his belief in his players despite their slow start to the season, after Saturday's victory lifted them two points above bottom-place Blackburn.
"I know we are good enough to get more points than we did last year," he insisted. "If we want to be lazy and assess things by the league table it will give us a lot of false information.
"It will be a challenging year but in football you need momentum and to play with confidence and belief.
"But if you keep playing well and losing it is difficult to create that momentum but in the last two weeks the team played without the fear. There was a feeling of having nothing to lose after a chain of defeats.
"How you deal with disappointment allows you to fulfil your potential and that is what my players have done.
"Today a few players were disappointed not to have made the starting line-up but the two subs who came on produced the winning goal."
Wigan found themselves held to a draw by Blackburn last weekend courtesy of a controversial Rovers goal, something Martinez conceded hit the morale of not only the players but also chairman Dave Whelan.
"When the ball went across the goal at the end I expected it to be offside with the bad luck we have been having," he said.
"The chairman [Whelan] is in Barbados and he was be so pleased because has was very down and upset after last week and this will be a real boost for him.
"I am glad we have won because I am sure he would have been making a few phone calls on the way back."