Yunchaokete Bu KOs top seed Tsitsipas in Winston-Salem

Yunchaokete Bu played a steady ground game and emerged with a 6-3, 6-2 upset win over top-seeded Stefanos Tsitsipas on Tuesday in the second round of the Winston-Salem (N.C.) Open.

Bu, a 23-year-old China native who is ranked 76th in the world, managed just nine winners to 25 from his Greek opponent. However, Tsitsipas committed 33 unforced errors while Bu gave away only 11 points.

Bu advances to face Argentina's Mariano Navone, who got past 16th-seeded Marcos Giron 6-2, 6-2.

Second-seeded Tallon Griekspoor of the Netherlands also stumbled in the second round as Hungary's Marton Fucsovics posted a 6-3, 4-6, 6-3 win. Third-seeded Luciano Darderi of Italy squandered a match point in the second-set tiebreaker before eventually topping Mackenzie McDonald 7-6 (5), 6-7 (6), 6-4.

The Netherlands' Botic Van De Zandschulp ousted sixth-seeded Matteo Arnaldi of Italy 6-3, 6-3. Eighth-seeded Alexandre Muller and ninth-seeded Giovanni Mpetshi Perricard, both of France, earned three-set victories. Tenth-seeded Sebastian Baez of Argentina, 12th-seeded Jaume Munar of Spain, 13th-seeded Miomir Kecmanovic of Serbia and 14th-seeded Roberto Bautista Agut of Spain also advanced.

Serbia's Hamad Medjedovic defeated 15th-seeded Jacob Fearnley of Great Britain 6-4, 7-6 (2).

In the highly anticipated final match of the evening, fifth-seeded Lorenzo Sonego of Italy outlasted local favorite Stefan Dostanic, 6-3, 6-7 (2), 7-6 (3). Dostanic, a former Wake Forest standout who is ranked No. 412 in the world, just debuted on the tour with a win over Australia's Aleksandar Vukic on Monday.

After winning the second-set tiebreaker, Dostanic broke Sonego in the first game of the deciding set. But leading 40-0 in the eighth game, the Irvine, Calif., native committed three unforced errors and Sonego evened the set at 4-4. Sonego, ranked No. 35 in the world, never trailed in the tiebreaker and advanced to the third round.

--Field Level Media