PSG midfielder Ander Herrera is baffled by Alexis Sanchez's problems as a Manchester United player.

The pair played together for 18 months following the Chilean's high-profile switch from Arsenal in January 2018. Alexis is currently on-loan with Inter Milan.

"Sometimes, in football, there is no explanation for every single thing that happens," Herrera told The Athletic. "Alexis is one of them. He came from Arsenal. He used to win games by himself for Arsenal.

"I remember watching him because Arsenal were our rivals for titles and the top four. I saw them losing games 2-0 and Alexis would score two and they'd win the game. He'd score the winning goal.

“It shows football sometimes has no explanation. How can a player, who one month before, two months before, is the best player by far in a big team like Arsenal… then he comes to United and he doesn't perform? I have no explanation."

Herrera claims Sanchez's failings at the club were not down to a lack of effort or ability.

"He trains good, he is a good professional, he tries to improve," Herrera added. "In training sessions, you can see his quality. He scores a lot of goals.

"In front of the goalkeeper in training, he was lethal, scoring goals, goals, goals. He fights if he loses the ball, he runs back and wins the ball, so he had everything to succeed at United, and he didn't do it.

"The only thing I can tell you is that I have no explanation."