December 2001 but feels it was a gamble worth taking.
Latics are now possibly only three games away from promotion and for Filan that would see an ambition fulfilled.
He told the Evening Post: "The club has done everything it promised it would three-and-a-half years ago when I came here.
"Back then, the gaffer sat down with me and told me he wanted to go places and the club didn't want to mess around.
"He realised I had come out of the Premier League and that one day I would want to get back to playing there.
"I took a bit of gamble coming to Wigan, they did the same with me, and hopefully they're happy with what I have done.
"One of the most difficult decisions of my career was undoubtedly coming here because I was giving up Premier League status.
"But at the end of the day, I wanted to play football regularly and Wigan have give me that chance ever since.
"These are exciting times for the club although the job is nowhere near finished and we still have another three games to play.
"If Wigan can get promoted, it would be beyond everyone's wildest dreams and now we have a realistic chance of doing it."
Filan, 35, agreed the new contract this week following lengthy negotiations stretching back some months.
He has put plans to return home to Australia on the backburner, saying he is good shape for another two years of football at a high level.
He said: "I'm pleased to have got the contract signed because it has taken quite a long time to sort out.
"I've struck a deal which I'm happy with and the club have me as a player for the next two seasons.
"I'm enjoying it here, there's a good atmosphere in the squad and thankfully the manager and club wanted me to stay around.
"There was always the temptation to go back to Australia but I made the decision 12 months ago that I wanted to play on in England if I was fit enough.
"My preference was always for that to be with this Wigan team.
"I had a couple of enquiries from other clubs but I wasn't really interested in going anywhere else if I could get a deal worked out here."
Filan has played more than 170 games for Latics since his move from Blackburn, missing just one league match in that time – last season's defeat to Wimbledon through suspension.
Manager Paul Jewell said: "John has been a major player for us over the last three-and-a-half years and has done ever so well.
"He's been an outstanding signing, missed very few games, and is calm and experienced.
"John has found a new lease of life here, he has enjoyed being part of a successful team and that has prolonged his ambition to carry on playing football."
Jason Roberts scooped Latics' first player of the year gong after picking up the Junior Latics award. Filan was runner-up and Leighton Baines third.
Season ticket holders have snapped up more than 2,600 of Latics' allocation for the game at Preston on April 30.
They go on general sale after the QPR game on Saturday.