The Austria international was a big fan favourite during a four-and-a-half year stint with the club after joining from Brann in 2005 and he had no hesitation in coming back on loan after a spell with Hamburg failed to work out.
With Maynor Figueroa and Antolin Alcaraz out injured, Scharner has become a key member of Wigan's back-four as the club again try to fight their way out of the Premier League relegation zone as well as ready themselves for the FA Cup final against Manchester City later this month.
"Paul has been a very good influence so far," said Martinez. "He brought a real experience at the back and has taken a lot of responsibility in helping the team to get results.
"Obviously he had prior knowledge of the club, which meant he didn't need any adaptation or transitional period.
"The relationship between the players and the fans is crucial at this stage of the season. Paul has always been an admired player by the fans and he brings that chemistry.
"It is important we are closer than ever because of the magnificent year it can be. We need to make sure we keep playing our football and use every opportunity in the league to get the points we deserve."