Paris Saint-Germain coach Laurent Blanc says form will decide who will start next week's Champions League game against Chelsea.
Ezequiel Lavezzi started the first leg at the Parc des Princes but was replaced by Javier Pastore late in the second half.
But this time, the 49-year-old could decide to start with the younger of the two in midfield at Stamford Bridge.
"We have to be calm in general," Blanc told reporters.
"It's an important game, we are in a unfavourable position but we will go all out for qualification.
"However, if we aren't calm, we will miss out.
"To decide which players will play against Chelsea, form will count.
"Between [Ezequiel] Lavezzi and [Javier] Pastore, their effectiveness will be important. One is a playmaker, the other is an striker.
"They haven't the same profile, but they must be more effective."
The Frenchman also wants striker Zlatan Ibrahimovic to perform in what could be one of his last chances to win the Champions League.
"Ibra isn't a young boy, he is 33," Blanc explained.
"Against Chelsea, he will have the same pressure on him as the whole team.
"He must score more because that's his role in the team.
"But he worked well during his two-match suspension. It's a good thing for him to return this weekend because he needs a competitive match before the game against Chelsea."
