British number three Dan Evans reached the Delray Beach Open final in Florida with 3-6 6-2 6-3 win over world number nine John Isner of the USA.
The 28-year-old world number 148, who returned in April 2018 from a one-year drugs ban, is a qualifier in the event.
He fought back to beat last year's Wimbledon semi-finalist Isner, 33, in an hour and 32 minutes.
In only his second ATP final he will face an unseeded player, either Mackenzie McDonald or Radu Albot.
American McDonald, 23, is the world number 84 who beat top seed Juan Martin del Potro in the quarter-finals.