Pastore has been shifted from a central midfield position to the right flank and delivered two sterling performances in a 2-1 Champions League win against Porto last Tuesday and a 4-0 thrashing of Evian Thonon Gaillard in Ligue 1 on Saturday.
"He is transformed," coach Carlo Ancelotti told reporters after Pastore, who had been hugely disappointing this season after joining for a then French record 42-million euro fee from Palermo last year, created the first two goals against Evian.
"His attitude on the pitch has changed. He has worked for the team, he has defended well and his skills made the rest."
PSG are second in the standings with 29 points from 16 games and trail leaders Lyon, who travel to basement side Nancy on Wednesday, by five points.
"This position in the midfield has forced me to defend more but this is what I have been training for," Pastore, whose delicate touches and inspired passes have wreaked havoc in the last two games, told reporters.
"I feel much better, more comfortable, because the team has been playing well. I feel good when the team enjoy possession and attack.
"The team's mentality has changed massively. Now, when we lose the ball, everybody makes efforts to get it back, not just one or two players."
While PSG visit one of the two teams who are unbeaten at home, Lyon face a seemingly easier task against Nancy, who have not won away all season.
Bottom club Nancy have drawn their last four games having wasted an early lead on three occasions.
Marseille, third on 29 points, should welcome the chance to play an away game at Bastia after losing their last two home matches and conceding seven goals in the process.
Wednesday's game, however, will be played behind closed doors after Bastia were sanctioned following crowd incidents in the league match against neighbours AC Ajaccio earlier in the season.
A few thousand supporters are expected to gather in the stadium's car park to watch the match on a giant screen.