World number four Dominic Thiem of Austria missed a chance to reach a career-best third in the ATP rankings with a Rio Open quarter-final loss Saturday to Italy's Gianluca Mager.
Mager, a 128th-ranked qualifier playing in only his eighth career tour-level match, defeated 2017 Rio champion Thiem 7-6 (7/4), 7-5 in a match that was halted Friday by rain.
Had Thiem reached the semi-finals in his 2020 clay-court debut, he would have overtaken Roger Federer for third in Monday's ATP rankings.
Mager served for the match in the ninth game of the second set but Thiem broke to pull level at 5-5, only to have the Italian claim the final two games and the match after one hour and 55 minutes on the court.
Mager booked a semi-final date against 106th-ranked Hungarian lucky loser Attila Balazs, who outlasted 133rd-ranked Spanish qualifier Pedro Martinez 2-6, 6-4, 6-2 in another rain-hit quarter-final.
Saturday's other semi-final pitted Chilean third seed Cristian Garin and fifth-seeded Borna Coric of Croatia, but rain again prevented those matches from being completed.
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