John Isner reached his fourth Hall of Fame Tennis Championships final as Alexander Bublik also moved into the decider.
Isner, a three-time champion of the ATP 250 event, edged past Ugo Humbert 6-7 (4-7) 7-6 (7-5) 6-3 in their semi-final on Saturday.
The American served 15 aces and claimed the only break of the match in the final set on the grass in Newport.
Humbert was unable to take his chances, failing to convert any of his seven break points in the defeat.
Bublik, 22, moved into his first ATP Tour final after overcoming Marcel Granollers.
The Kazakh battled to a 7-6 (7-5) 3-6 6-4 victory over Granollers despite serving 14 double faults.