Failure made me stronger - Dufner

US PGA Championship winner Jason Dufner says that past failures made him a better player and allowed him to clinch his maiden major title.

At the same tournament two years ago he blew a five shot lead with four holes to play, eventually losing in a playoff to Keegan Bradley.

There was no such collapse at Oak Hill as Dufner beat Jim Furyk by two shots to win golf's final major of the season.