Angel Di Maria must change his attitude and make a greater effort to help Paris Saint-Germain out of their slump in form, Jerome Rothen says.
Di Maria, 28, has yet to find the net and provided just two assists in the opening seven league games this term in which PSG have already lost twice, as many defeats as they suffered in the whole of last season.
The Argentina international was again below his brilliant best in PSG's Champions League win over Ludogorets Razgrad on Wednesday, prompting former PSG man Rothen to question Di Maria's mental approach to matches.
"His problem is his attitude," Rothen told RMC. "When he goes into matches, he doesn't put himself in 'I'm going to be a warrior, I'm going to run, I'm going to make an effort' mode.
"He doesn't put in enough effort. He has to be given a stern talking to, like Ben Arfa. 'You change your attitude or you're not in the squad.' But it's difficult to do with players who are signed for so many million euros, with a status, with titles..."
A reported £44 million pound signing from Manchester United in 2015, Di Maria ended his first season in France with 18 assists, which represented a Ligue 1 high and was five more than Zlatan Ibrahimovic, his nearest competitor.
After the French champions' win in Bulgaria, during which Di Maria managed just one shot on target from four attempts, Emery acknowledged his star attacking midfielder's form was the subject of debate.
"It's a question we talk about a lot in the dressing-room to improve performances," the former Sevilla coach said. "Di Maria is a very important player for us. I want to trust him, I want the players to trust him. I'm happy for him, because he is very committed."