Manchester United boss Ole Gunnar Solskjaer says Alexis Sanchez must dig himself out of his form slump after his disappointing display last night.

Sanchez was introduced for Jesse Lingard shortly before half-time at Old Trafford but under-performed as PSG scored twice within 15 minutes of the restart to secure the Champions League first-leg win.

Sanchez may start the FA Cup fifth round tie at Chelsea on Monday if Anthony Martial and Lingard fail to recover but Solskjaer insists he is powerless to improve Sanchez.

"I can't do anything about Alexis Sanchez," Solskjaer said. "When he plays he needs to find himself because we know there's a quality player there."