Kei Nishikori and David Ferrer will meet in the Mexican Open final after three-set victories on Friday.
The top two seeds at the ATP 500 event played on hard courts claimed wins in Acapulco, setting up a decider.
Nishikori fought his way past Kevin Anderson 6-2 3-6 6-3, while Ferrer outlasted qualifier Ryan Harrison 4-6 6-0 6-0.
The top-seeded Nishikori extended his winning run to eight matches by battling past the South African fourth seed, who was runner-up last year.
Nishikori was dominant in the first set as he broke twice, but his serve let him down in the second to give Anderson a way back into the match.
Anderson managed to break once in the second set, with Nishikori serving at a poor 29 per cent, on his way to levelling the match.
When he broke for a 1-0 lead to start the third set, Anderson looked in control.
But he conceded the next four games, with Nishikori breaking twice and then saving two break points in the fifth game.
There was no way back for Anderson as Nishikori's good run of form continued.
Awaiting him in the final is another player in form, with second seed Ferrer getting past American Harrison.
Harrison took the first set but it went wrong from then on, winning just four return points in the final two sets.
Three-time champion Ferrer lost just seven points in the deciding set to close out victory in one hour, 51 minutes to extend his winning run to nine matches.
The Spaniard's last loss was at the Australian Open, where he was beaten by Nishikori.