Rhode Island - Three-time champion John Isner fended off fourth-seeded Frenchman Ugo Humbert 6-7 (4/7), 7-6 (7/5), 6-3 on Saturday to reach the final of the ATP grass court tournament in Newport, Rhode Island.

Isner, trying to get his season back on track after he was sidelined by a stress fracture in his foot after reaching the final in Miami in April, will take on seventh-seeded Alexander Bublik of Kazakhstan, a 7-6 (7/5), 3-6, 6-4 winner over Spain's Marcel Granollers.

In sweltering heat, Isner and fourth-seeded Humbert played the first two sets without a service break.

Isner's miscue on a backhand volley at 2-2 in the first-set tiebreaker was the only opening Humbert needed to pocket the set. Isner double-faulted early in the second-set tiebreaker, but won five straight points as he rallied to level the match - firing a stinging backhand winner on his second set point.

The US veteran was in control throughout the third, breaking for a 2-0 lead and serving out the contest on his first attempt.

But he'll face another hungry youngster in Bublik, who like Isner has needed three sets for all of his victories this week.

I've worked hard for this, so I'm very happy," Bublik said.

"I have to try and be the best version of myself for tomorrow, so we'll see what happens."

Results on Saturday in the ATP grass court tournament at Newport, Rhode Island (x denotes seeded player):

Semi-finals

John Isner (USA x1) bt Ugo Humbert (FRA x4) 6-7 (4-7), 7-6 (7/5), 6-3

Alexander Bublik (KAZ x7) bt Marcel Granollers (ESP) 7-6 (7/5), 3-6, 6-4