The 57-year-old Spaniard replaces David Moyes, who left when his contract expired at the end of the season.
It is two-and-a-half weeks since Manchester United capitulated at Crystal Palace but one scene from Selhurst Park remains scorched in Diogo Dalot’s mind as he heads into Saturday’s FA Cup final at Wembley.
Keep up to date with all the latest summer transfer news and rumours