Haider-Maurer took the place in the draw of Ernest Gulbis, who withdrew for personal reasons, and has advanced to the semifinals with a 7-6 (7-1) 6-4 win over second-seeded Marin Cilic.
Haider-Maurer, No. 157 in the world, dropped serve just once and won 74 percent of the points on serve. He lost five points on serve in the second set when he didn't face a break point.
Michael Berrer also posted an upset Friday, knocking off No. 4-seeded Marcos Baghdatis 5-7, 6-1, 6-4. He had to deal with only one break point on the day -- it cost him the first set -- and ended up taking nearly 80 percent of the points when he served.
Third-seeded Nicolas Almagro also made the semifinals, getting past No. 8 Juan Ignacio Chela 7-5, 3-6, 6-3 while top-seeded Jurgen Melzer advanced when seventh-seeded Philipp Kohlschreiber couldn't play due to a groin injury.
Saturday's semifinals have Melzer going against Almagro while Haider-Maurer and Berrer meet in the other match.