Top-seeded Argentine Juan Martin del Potro got a stern test from speedy Damir Dzumhur in the semi-finals of the Los Cabos Open but came away with a 6-3, 7-6 (8-6) victory.
He will next take on second-seeded Italian Fabio Fognini, a 6-4, 6-2 winner over the United Kingdom's Cameron Norrie, in the final of this hard-court event in western Mexico, reports EFE news agency.
Del Potro traded breaks with his third-seeded Bosnian opponent in the first two games of their Friday-night semi-final.
But the Argentine got his nose in front again when he broke serve in the eighth game on a forehand error by Dzumhur and then wrapped up the set with a service hold.
Del Potro appeared to seize total control of the match when he broke to start the second set and then fought off a break point to grab a 2-0 lead.
The world No. 4 had a chance to serve out the contest in the 10th game, but he got broken for the second time in the match partly due to a costly double fault and the second set came down to a tie-breaker.
Del Potro was unable to create any breathing room in the "breaker" and even needed to produce a backhand down-the-line passing shot winner to stave off a set point.
But the Argentine's lethal forehand emerged at critical junctures, including on match point, to give him the decisive edge.
"It was a good fight from him. We played good tennis, especially in the second set," Del Potro was quoted as saying on the ATP World Tour's Web site. "I made some mistakes in the end of the set, but then I played a smart game in the tie-break. I took my chances to win and I'm glad to reach another final this season."
Del Potro will square off in the championship match against the 15th-ranked Fognini, whose strong return game was the difference once again in his win over Norrie.
The Italian broke Norrie's serve four times on Friday night and has racked up 13 service breaks in three matches at this year's Los Cabos Open.
"It will be tough tomorrow against Fabio," Del Potro said. "But anything can happen in the final, so I will try to do my best."
The Los Cabos Open is a tune-up event for the US Open, which gets under way on August 27.