Manchester United purchased Blomqvist as a backup to Ryan Giggs in the early stages of the 1998-99 season, for a fee of £4.4 million, three years after manager Alex Ferguson had first attempted to sign him for United from IFK Gothenburg. He featured in enough games to win a Premier League winner's medal in the 1999 season, scoring his only goal for the club in a 4–1 away win against Everton. He received an FA Cup winners medal despite being an unused substitute in the final. He did, however, start against Bayern Munich in the Champions League final. He came close to scoring before eventually being replaced by Teddy Sheringham, who later scored a late equaliser after Bayern's early goal. United went on to win the match 2–1.