Bulgaria's Grigor Dimitrov edged second-seeded Andy Murray in three sets on Friday to reach the final of the ATP Mexico Open, where he'll face South African Kevin Anderson.
The fourth-seeded Dimitrov, who had never beaten Murray in three prior encounters, triumphed 4-6, 7-6 (7/5), 7-6 (7/3).
Dimitrov needed two hours and 54 minutes on the Acapulco hard court to seal the victory, giving a leap of triumph as Murray's forehand found the net on match point to bring things to a close at 2:30 am.
After taking the second-set tiebreaker on his third set point, Dimitrov gained the advantage in the third set by breaking Murray in the opening game.
But he looked shaky as he tried to serve out the match in the 10th game, a spate of errors helping Murray break back to knot the set at five games apiece.
Murray saved two break points in the next game to take a 6-5 lead and Dimitrov, serving to stay in the match, held at love to force the tiebreaker.
Murray had started the match strongly, breaking Dimitrov in the very first game and breaking again for a 4-1 lead.
But neither player faced a break point in the second set, and it was Dimitrov who looked the more confident as he built a 5-1 lead in the tiebreaker.
Murray saved two set points on his own serve, before Dimitrov converted his first opportunity on his own serve to knot the match at one set apiece.
The fifth-seeded Anderson secured his second ATP Tour finals berth in as many weeks with a 6-1, 5-7, 6-4 victory over Ukrainian Alexandr Dolgopolov.
Anderson, 27, arrived in Acapulco off a runner-up finish to Marin Cilic in Delray Beach.
He needed two hours to get past Dolgopolov, firing 19 aces and breaking the Ukrainian three times.
In the women's final of this combined ATP and WTA tournament, Australian Open runner-up Dominika Cibulkova will take on American Christina McHale.
The top-seeded Cibulkova was leading eighth-seeded Zhang Shuai 4-2 in the opening set when the Chinese player retired from the match.