Manchester United boss Jose Mourinho has backed Alexis Sanchez "to be great" for the club next season.

United brought Sanchez to Old Trafford during the January transfer window, and the Chile international initially struggled to show his best form for the 20-time English champions.

The 29-year-old has impressed in recent weeks, however, starring in United's 3-2 win over Manchester City in the Premier League before netting against Tottenham Hotspur in the semi-finals of the FA Cup last weekend.

"He was playing in our competition for years - we all know how good he was. That's why he was chased by many teams I believe, that's why we fought to have him here and I was, since day one, sure he was the right player," Mourinho told reporters.

"Not just by the typical football qualities but also by his mentality and we needed that, a little bit more experience, mental aggressiveness and I knew sooner or later were coming.

"I don't like the January market but was now or never and now if we can have good Alexis until the end of the season better for us. We need seven points, we have a final to play. Can he help us? I hope so and next season after pre-season, after being comfortable and adapted he's going to be great for us."

Sanchez's former club Arsenal will visit Old Trafford in the Premier League on Sunday afternoon.