Dominic Thiem, playing in his first tournament on American soil since winning the 2020 US Open, defeated top-seeded Grigor Dimitrov in the second round of the Winston-Salem Open after Dimitrov retired because of dizziness.
Dimitrov was leading the match 6-0, 2-4 at the time.
“That’s not the way I want to win a match, especially against Grigor,” Thiem said.
Thiem reached a career-high No. 3 in the world rankings in March of 2020 and remained in the top five until injuring his right wrist 14 months ago.
Maxime Cressy of the United States, the No. 4 seed, moved into the third round with a 6-3, 6-3 win over Australia’s James Duckworth, and fellow American Steve Johnson defeated No. 12 seed Pedro Martinez of Mexico 7-6 (2), 6-2.
Fifth-seeded Lorenzo Musetti from Italy was upset in the second round by France's Richard Gasquet 7-6 (5), 4-6, 6-1, and No. 6 seed Nikoloz Basilashvili from Georgia fell to Brazil's Thiago Monteiro 6-4, 6-1.
Gasquet's countrymen Adrian Mannarino and Benjamin Bonzi also advanced with second-round wins, capping a big day for France. Mannarino defeated ninth-seeded Emil Ruusuvuori of Finland 6-4, 6-1, while the 10th-seeded Bonzi eliminated Germany's Peter Gojowczyk 6-4, 6-2.
Australia's Jack Draper and Jason Kubler also won, along with Serbia's Laslo Djere, who beat 16th-seeded Joao Sousa of Portugal 4-6, 6-3, 7-6 (5).
In doubles action, the No. 1 seeded team of Nikola Mektic and Mate Pavic from Croatia advanced with a 6-4, 6-3 win over Ukrainian-Kazakhstani's Aleksandr Nedovyesov and Pakistan's Aisam-ul-Haq Qureshi. However, second-seeded Ivan Dodig of Croatia and Austin Krajicek of the United States were ousted by Simone Bolelli of Italy and Marcelo Melo of Brazil 6-4, 7-6 (3).