Miami - US fourth seed Reilly Opelka rallied to defeat Canadian second seed Milos Raonic 4-6, 7-6 (8/6), 6-3 Sunday to reach the Delray Beach Open final.

The 22-year-old American, whose lone ATP title came at last year's New York Open, will play for the title later on Sunday at the rain-hit Florida venue against Japan's 63rd-ranked Yoshihito Nishioka.

Opelka beat Nishioka 6-4, 6-4 last week in the second round at New York in their only prior meeting.

In a match postponed by rain from Saturday night, Raonic took the lone break of the first set and battled into a second-set tie-breaker, which Opelka led 5-0 before the Canadian roared back with six points in a row.

Opelka blasted his 15th ace to save match point, then watched Raonic send two forehands beyond the baseline to force a third set.

Raonic send a backhand wide to surrender a break in the seventh game of the final set and Opelka blitzed him in the last game to advance after two hours and seven minutes.

Nishioka, who won his only prior ATP final in 2018 at Shenzhen, ousted French sixth seed Ugo Humbert 1-6, 6-4, 6-0 on Saturday before the rain.

The 24-year-old is projected to crack the ATP's top 50 for the first time in Monday's rankings.

Results on Sunday from the ATP Delray Beach Open (x denotes seeding):

Semi-finals

Reilly Opelka (USA x4) bt Milos Raonic (CAN x2) 4-6, 7-6 (8/6), 6-3

Playing later

Final

Yoshihito Nishioka (JPN) v Reilly Opelka (USA x4)