Veteran Karen Khachanov of Russia rallied from a two-sets-to-one deficit and denied Learner Tien a spot in the quarterfinals with a 7-5, 4-6, 6-7 (6), 6-1, 6-4 victory in the U.S. Open fourth round on Monday night in New York.
The match lasted 3 hours, 50 minutes, with 323 points played.
In the last match of the evening, top-seeded Alexander Zverev of Germany rolled past 21st-seeded Luciano Darderi of Italy 6-2, 6-2, 7-6 (3).
Tien was bidding to become the fourth American to reach the quarterfinals. Ben Shelton, Frances Tiafoe and Alex Michelsen advanced and will play on Tuesday. Tiafoe and Michelsen will face each other, while Shelton will meet two-time U.S. Open champion Carlos Alcaraz of Spain.
Khachanov will face Belgian Alexander Blockx, who knocked off Argentina’s Francisco Cerundolo, 6-3, 4-6, 7-5, 7-5 in the first round-of-16 match of the day.
Blockx became the first Belgian man to reach the U.S. Open quarters and pulled it off in his debut in New York.
Tien, the 20-year-old No. 14 seed, fell behind 4-1 in the third-set tiebreaker, but won seven of the next nine points to take the lead and momentum into the fourth set.
But it was short-lived, as Khachanov won 16 of the first 21 points in the fourth to take a commanding lead and send the match to a decider.
There was an exchange of early breaks in the fifth set, and the big-hitting Russian put pressure on Tien’s serve by taking a 5-4 lead. He capitalized, breaking Tien for the ninth time in the match to advance to his first Grand Slam quarterfinal since reaching the Wimbledon final eight in 2025.
“It was a really crazy match,” said Khachanov. “We played for the first time against each other. I knew what to expect: One extra ball coming back, one extra ball. So many close rallies. He loves to play that defense outside the court, that’s why it makes it extremely tough, this match, because you have to stay always in the match with great intensity, hitting, hitting, pushing. In the end, I’m super happy that I could pull through.”
Blockx, who had defeated No. 5 Flavio Cobolli of Italy on Saturday, saved 14 of 17 break points in the match and secured key breaks in the latter stages of the third and fourth sets.
The 21-year-old, who began the year ranked outside the top 100, rallied from 30-love down in the 12th game of the third set and converted his second break point.
The fourth set featured no breaks of serve until the fateful 12th game for the 24th-seeded Cerundolo. They split the first two points of the game, but Blockx won three straight to move on.
It almost wasn’t to be as the Belgian took a medical timeout at 3-2 in the first set.
“From the second game I started feeling really sharp in my rib,” Blockx said following the three-hour, 16-minute clash. “I was just holding on to be honest. Even though I won that first set 6-3, it could have been the other way round. Afterwards, the doctor gave me some magical medication and that kept me going and from the end of the third set I started to feel a lot better again. I barely felt pain.”
In a five-hour, 13-minute marathon, the Netherlands’ Botic van de Zandschulp staved off a third-set match point and rallied to defeat French lucky-loser Arthur Gea, 3-6, 6-7 (0), 7-6 (7), 7-6 (3), 6-4, reaching his second Grand Slam quarterfinal.
In the process, he dashed the hopes of Gea, who would have been the first lucky loser in the Open era to reach the quarterfinals. Gea lost in qualifying but qualified for the tournament after Norway’s Casper Ruud withdrew due to injury.
The 21-year-old Frenchman led the third-set tiebreaker 4-1 and served at 6-5, needing one point for victory. But he failed to convert a volley, then smashed a ball well into the stands. Van de Zandschulp prevailed 9-7, and Gea smacked his racket against his bag in frustration after the set.
In a 16-point seventh game of the deciding set, the Dutchman broke through on his fifth break point opportunity. He repelled one break point in the final game before ending the match.
Van de Zandschulp next will face Zverev for the first meeting of their careers.
Zverev saved the lone break point he faced against Darderi, but he converted only four of his 17 break chances.
“I thought my level was very consistent,” Zverev said. “He started playing incredibly well in the third set. I barely saw anyone hit the ball as hard as he did, consistently for an entire set, so credit to him. He made it very difficult for me, but I’m happy to be in the quarterfinals and happy to be playing this way.”
Zverev is looking for a strong finish to an impressive season that has seen him reach the semifinals of the Australian Open, win his first Grand Slam title at the French Open, then reach the final at Wimbledon.
–Field Level Media
