DUNEDIN, NEW ZEALAND - APRIL 01: Matt Faddes of the Highlanders passes the ball during the round six Super Rugby match between the Highlanders and the Western Force at Forsyth Barr Stadium on April 1, 2016 in Dunedin, New Zealand. (Photo by Rob Jefferies/Getty Images)

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.