Grigor Dimitrov tamed the big serve of John Isner, with the Bulgarian posting a 7-6 (7-4) 7-6 (12-10) win to book a spot in the final of the Cincinnati Masters.
The seventh-seeded winner will wait for a Sunday opponent as Australian Nick Kyrgios and former finalist David Ferrer meet in the other semi-final on Saturday.
Dimitrov took step towards regaining control of his season as he pulls out of a slump.
He won two titles and posted a 16-1 record in the early months of 2017, but has since seen his level drop.
A week after losing early in Montreal, the 26-year-old came alive in the last major event prior to the start of the US Open a week from Monday.
“I want to have these tough matches before the last grand slam of the year,” Dimitrov said.
“It shows I’m able to take the right decisions, tomorrow will be a step further for me.”