Fourth-seeded David Ferrer defeated seventh-seeded Ivo Karlovic of Croatia 6-7 (2), 7-6 (5), 7-6 (4) to make the Qatar Open final on Friday.
Ferrer will play either third-seeded Tomas Berdych or Andreas Seppi of Italy in Saturday's final.
There were no service breaks by Ferrer or Karlovic during their intense 2-hour, 32-minute match.
Ferrer lost his serve to trail 3-2 in the third-set tiebreaker. Karlovic lost the next two points on serve to set Ferrer up for the win.
Karlovic saved the first of two match points for Ferrer at 6-3 with a second-serve ace, his 30th of the match and 97th of the tournament.
Karlovic improved his career tally to 9,092 aces. He surpassed Andy Roddick (9,074) to lie second only to Goran Ivanisevic (10,183); they are the only three players since 1991 to serve more than 9,000 aces.