Kei Nishikori has defeated American teenager Taylor Fritz to win a historic fourth Memphis Open title.

Nishikori won the match 6-4, 6-4 in one hour and 19 minutes.

The world No.7 joins Roger Federer, Rafae Nadal and Novak Djokovic as the only current active players to win four consecutive titles at a singles tournament.

Fritz reached his first ever ATP World Tour Final in just his third tour-level event, beating German Benjamin Becker and Australian and seventh seed John Milman during a memorable week for the 18-year-old.

The American got off to a flying start, winning 12 of the opening 14 points and claiming the first break of the match for a 2-0 lead.

However, Nishikori settled and broke straight back, eventually claiming the first set 6-4, before breaking midway through the second to claim a straight sets win.

The win was Nishikori's 11th ATP World Tour title.