Former Manchester United manager Sir Alex Ferguson has said his tough approach with players may have cost the club silverware during his time there. Roy Keane, Jaap Stam, David Beckham and Ruud van Nistelrooy were among the high-profile players who fell out with Ferguson during his 26 years in charge. The Scot won 38 trophies, including 13 league titles, two Champions Leagues, five FA Cups and four League Cups. The 73-year-old said: "I place discipline above all else." Writing in his new book Leading, Ferguson added: "It might have cost us several titles. If I had to repeat things I'd do it precisely the same."