Alexis Sanchez has apologised to Manchester United supporters following Sunday's defeat to Cardiff City.

United finished the season in their second-lowest position since 1990 and recorded their worst defensive record in 40 years.

In an apology posted on Instagram, Sanchez says he's "certain" the club will return to the glory days of the Sir Alex Ferguson era.

"It was a very tough season...the fan are the ones who deserve an apology as they always support you no matter what happens," Sanchez explained.

"Personally, I didn't perform as much as I was expecting because of unpredictable injuries.

"Press and people were speculating of things that were not even true. I was always a professional in all aspects.

"I apologise to the fans for not be able to achieve our goals. Nevertheless we are Manchester United!

"Players and Staff are questioning if we were doing the right thing and if we were giving our best for this football shirt ... I'm certain that Manchester United one day will return to be the club, as it was in the old days with Mr. Alex Ferguson."