Sir Alex Ferguson believes no player has ever made as great a mark on his title-winning teams as Robin van Persie has done this season.
The Dutchman clinched Manchester United's 20th league title with a hat-trick to defeat Aston Villa and ensure they have won the league with four games to go. It took Van Persie's tally to 28 goals for the season since his £24 million move from Arsenal and his league strikes have been worth 25 points to Arsenal.
Cristiano Ronaldo scored 42 goals in the 2007-08 campaign while Eric Cantona made huge contributions in 1993-94 and 1995-96, while Ferguson has also managed such United greats as Roy Keane, David Beckham, Ryan Giggs and Ruud van Nistelrooy.
But he said: "In terms of impact I think he has made as big an impact as any I can imagine. Cantona was a big-impact player I'm very lucky I've got some amazing strikers."
And Ferguson said that Arsene Wenger, who reluctantly sold Van Persie to United in August, told him to expect an even better footballer than he realised.
He added: "I think Robin is such a great player for Arsenal and when a great player becomes available and you feel United should have him you have to go for him. I think we had an expectation of him - his performance last season was incredible. I remember Arsene saying 'he's a better player than you think.' I knew he could gel into the team."
Van Persie's second goal against Villa was a memorable long-range volley and Ferguson jokingly branded it "the goal of the century."
He said: "The goal tonight, it doesn't matter where you place that with all the great goals from David Beckham, Ole Gunnar Solskjaer, Cantona, that takes place with that."
After a two-month goal drought, Van Persie has now scored five goals in three games and is leading the race to win the Golden Boot.
And Ferguson said: "He has been unbelievable. His early form that first six months was fantastic. He hit that spell where he hadn't scored a goal and every striker has a dry spell but when he scored that penalty kick at Stoke I thought, he's alive now and today he was unbelievable."