WASHINGTON — Kevin Anderson survived a tense third-set tiebreaker to upset top-seeded Dominic Thiem and advance to the quarterfinals of the Citi Open.

The 6-foot-8 South African veteran fought off a match point before serving out the tiebreaker to win 6-3, 6-7 (6), 7-6 (7) on Thursday night and improve his career record to 6-0 against the seventh-ranked Thiem. The match lasted 2 hours, 46 minutes.

The Citi Open is a hard-court tuneup for the U.S. Open, which starts July 28. Anderson's three career titles have all come on hard courts. Thiem has three titles this season, two on clay, and he reached the semifinals at the French Open.

Third-seeded Milos Raonic, the 2014 Citi Open champion, won a lengthy first-set tiebreak on the way to beating Marcos Baghdatis 7-6 (7), 6-3, and eighth-seeded Jack Sock beat fellow American Jared Donaldson 7-6 (6), 6-2. Raonic and Sock will face each other in the next round.

In the women's draw, Canadian wild card Bianca Andreescu knocked off second-seeded Kristina Mladenovic in straight sets to advance to the quarterfinals.

Andreescu beat Mladenovic 6-2, 6-3 on Thursday. In other women's matches, top-seeded Simona Halep came back from losing the first set to beat Mariana Duque-Marino 3-6, 6-4, 6-2, and Andrea Petkovic beat Eugenie Bouchard 6-2, 4-6, 6-0.

Five of the top seven seeds in the women's draw reached the quarterfinals.