The Bloomfield Road assistant faced the media in the absence of Barry Ferguson, and was purring after goals from Andy Keogh and Stephen Dobbie went a long way towards securing their Championship status for another season.
"It was a massive win for us," Thomas said.
"But over the last few weeks the group has got stronger and stronger, the belief has got stronger and stronger, and we went about the job properly.
"We've spoken a lot about positivity and being positive, and it is easy for your shoulders to go down in this situation.
"But it's something we've worked on, our behaviour about the place, building up to games.
"The group has worked incredibly hard to get where they are right now, and we've never looked negatively at it.
"We came here with a firm belief we'd win the game, and that's exactly what we did."
Blackpool dodged a bullet on the half hour when Martyn Waghorn's penalty was brilliantly saved by Matt Gilks.
And two goals in the space of 11 minutes after the break secured the Seasiders a league double over their north-west neighbours.
"Big Gillers has made the save - that's what he's paid to do - and that gave us a big boost," Thomas added.
"We went on to gain control of the game in the second, we totally dominated, and scored two good goals.
"We knew in the second half we would have more energy than them, based on the training that Barry has been doing with them.
"There is high energy within the team and we knew we'd get more of the ball after the break and create opportunities for ourselves."
Thomson also recognised the contribution of the 3,500 away supporters - 3,000 of whom had taken advantage of free tickets provided by the club to ensure a boisterous backing.
"The supporters were fantastic for us," Thomson enthused. "To look up and see that orange army in the stand, it was great.
"Credit to them, they played their part in our win. They definitely helped us to win the game."
Wigan now need three points from their last two games - at Birmingham and Blackburn - to secure their play-off spot.
Boss Uwe Rosler believed the turning point in this one was not Waghorn's penalty miss, but the disappointing manner in which they conceded the first goal.
"We've analysed Blackpool well in recent weeks and we knew what to expect," Rosler said.
"They have been very good against the ball and they have been better organised than they have been for much of the season.
"We knew it would be difficult to break them down.
"Yes we can play a lot better, but in the first half we put in a decent half of football.
"We generated a penalty, which is the best chance of scoring in modern football, and two or three other good shooting chances.
"Defensively we were rock solid - they did not have one shooting opportunity, not one.
"The message was clear, to continue the same way, because it was working.
"But the first goal...when you let the ball bounce, as a defender, you have a problem.
"And that cost us the game. The first goal was decisive based on the way Blackpool were set up - everybody behind the ball."