Blockx beats seed No.5 Cobolli to reach a first Grand Slam fourth round at 21

Flavio Cobolli had lost the opening set in each of his first two matches and won both. On Saturday evening he won the opening set for the first time this fortnight, and lost. Alexander Blockx, 21 years old and playing his first US Open main draw, beat the No. 5 seed 6-7 (4), 6-3, 6-0, 6-3 to reach the fourth round of a Grand Slam for the first time.

The Belgian, the No. 28 seed and ranked No. 34, took 19 of the 22 games after the tiebreak, including a third set to love.

It was decided on serve, in both directions. Blockx hit 17 aces and 41 winners against four double faults, and won 86% of the points behind his first serve and 62% behind his second. Cobolli landed exactly the same proportion of first serves, 57%, and won 59% of those points and 42% of his second-serve points.

The second top-10 win of Blockx’s young career

It is the second time Blockx has beaten a top-10 player. The first came earlier this season in Madrid, against Felix Auger-Aliassime, then ranked No. 5, who went out of this tournament in the second round on Thursday.

He had reached the third round by beating Argentine Marco Trungelliti 6-3, 6-2, 3-6, 6-1 and Chilean qualifier Tomas Barrios Vera 6-3, 6-4, 6-2.

Cobolli’s fortnight had already required more of him than the seeding suggested. The Roland-Garros runner-up needed four sets to get past Australian qualifier Tristan Schoolkate, 3-6, 6-3, 6-4, 7-5, and then came from two sets down for the first time in his career at a major to beat Argentine Francisco Comesana 3-6, 2-6, 6-3, 6-4, 6-4 across four hours and 12 minutes. He had been 0-8 in that situation before Tuesday.

He was also trying to reach the fourth round of a Grand Slam on hard courts for the first time in his career, having gone out in the third round in each of his three US Open appearances.

Blockx plays Argentine Francisco Cerundolo, the No. 24 seed, who beat Taylor Fritz from two sets and a break down on the same evening.

US OPEN 2026, men’s singles, round of 16

A. Zverev [1] vs A. Tabilo [25] – not played
L. Darderi [21] d. D. Sweeny (W): 6-4, 6-3, 6-3
M. Zheng (W) vs A. Gea (L) – not played
Z. Bergs [31] vs B. Van de Zandschulp – not played
K. Khachanov d. B. Bonzi: 6-3, 6-2, 6-4
J. Mensik [17] vs L. Tien [14] – not played
F. Cerundolo [24] d. T. Fritz [9]: 3-6, 4-6, 6-3, 6-4, 6-4
A. Blockx [28] d. F. Cobolli [5]: 6-7(4), 6-3, 6-0, 6-3
D. Medvedev [7] d. A. Rinderknech [26]: 6-4, 6-4, 6-4
F. Tiafoe [11] d. V. Vacherot [22]: 6-4, 6-2, 6-4
A. Michelsen d. D. Merida: 7-6(5), 6-4, 6-3
T. Etcheverry [27] d. M. Navone: 6-4, 6-4, 6-3
B. Shelton [8] d. D. Shapovalov: 7-6(3), 6-7(5), 6-3, 6-4
S. Tsitsipas d. J. Lehecka [18]: 2-6, 6-1, 7-6(3), 6-1
T. Paul [20] d. Y. Wu: 6-4, 3-6, 6-7(4), 6-1, 6-3
C. Alcaraz [2] d. A. Bublik [15]: 6-3, 6-4, 6-1