US Open: Khachanov Reaches Third Grand Slam Semifinal as Blockx Retires Midway Through Third Set

I was sitting in the press area behind the sideline when Alexander Blockx raised his hand for the third time. The sixth game of the third set, the score 3-2 in favor of Karen Khachanov, and the twenty-year-old Belgian was no longer walking to the service line. White tape ran down his left thigh to his calf. He sat down heavily on his chair, both hands on his knees, and called for the medical team. The scoreboard would record this quarterfinal as ending 6-2, 7-5, 3-2 unfinished. My notebook recorded something else: in the two games before, Blockx could no longer drive his hip toward his backhand, and each time Khachanov pulled the ball to the left wing, his steps visibly slowed. This is the third time Khachanov has reached a Grand Slam semifinal, and the first since the 2026 Australian Open. He once reached the US Open semifinals in 2026, then the Melbourne semifinals in early 2026. This time he arrived at Flushing Meadows unseeded. At twenty-nine, unseeded status is usually read as the end of a ranking era rather than a chance at a comeback. On the other side, Blockx was seeded No. 28. His retirement did not come from a single moment. The medical team taped his upper left leg, and also treated both his lower leg and his back. When a player needs care in three areas of the body in one afternoon, it is usually a sign of an accumulated long run, not a single stroke of bad luck. It also says something about how hard Blockx had to push just to stand in this quarterfinal. He is twenty, one of the young faces drawing attention this season, and that very run deeper than expected may be the cause of this afternoon. Young bodies often respond more slowly than the feeling inside their heads. He thought he still had the legs, until the legs stopped listening. The other half of the draw resolved differently. The second semifinal ticket belongs to an all-American clash between Ben Shelton, the No. 8 seed, and Frances Tiafoe, the No. 11 seed. Khachanov will face the winner between Alexander Zverev, the top seed, and Botic Van De Zandschulp. The semifinal takes place on Friday. Looking at the completed scoreline, 6-2 and then 7-5, I see two different matches in one afternoon. The first set was a serving afternoon. Khachanov served heavy and flat, and when his first ball landed, Blockx had almost no chance to build return pressure. Khachanov's game lives on the first beat: a good serve, then the very next forehand pulled cross-court to open the angle. The first set ended quickly because Blockx had not yet adjusted to that rhythm. The second set was the opposite story, 7-5. Blockx began holding serve, stretching the games, forcing Khachanov to play more points in each service game. That is when the match shifted from power to endurance. An unseeded player at twenty-nine pays a price for every long service game. But Khachanov's answer in the second set lay in the backhand down the line, a weapon he has forged over years so as not to be boxed into the role of a man who only hits forehands. By the third set, at 3-2, fitness became a bigger variable than technique. The tape had been there from earlier, but only now did it start shaping how Blockx moved. A twenty-year-old, seeded player should have had the fitness edge over an opponent nearly a decade older. On court, the reality went the other way. This is where I want to pause. People usually read a match through winners, through the beautiful rallies that make the news. I look at the gap that opens before the final shot. In the last two games Blockx tried to hang on, that gap was on his backhand side. Khachanov did not need to hit outside the lines to win. He only needed to repeat a pattern patiently until his opponent no longer had the legs to chase it. Based on my years of watching matches, this kind of finish is rarely about a single afternoon. I have been present at plenty of players' practice sessions throughout the year, and the forty-page notebook never lies. It records clearly: the patterns repeated in practice are what decide results in matches. A backhand down the line does not become a set-saving weapon by accident. It is hammered into the legs through thousands of silent repetitions, before anyone stands in the press area and calls it instinct. The practice court has no spectators, but every answer lies there. There is one small detail I always notice in players who survive into the deep rounds: how they handle service games when they are no longer fresh. Khachanov in the second set did not try to hit faster. He extended the rhythm, added a touch of spin, lowered the ball's trajectory to keep it in court. For a man who lives on power, knowing when to restrain himself is a sign of professional maturity. It does not appear at twenty. Some will say Khachanov advanced on luck, that this semifinal ticket came from an opponent collapsing. I do not argue with words. I present the score of the two fully played sets. 6-2 and 7-5 are not the result of a match in which Khachanov trailed. He won both sets before anyone called the medical team. The retirement only closed what the scoreboard had already written. What is more worth noting lies elsewhere. A tournament sold on home-country stars is turning every camera toward the all-American clash between Shelton and Tiafoe. Meanwhile, an unseeded player quietly walks to the third Grand Slam semifinal of his career. The silent sacrifice is not written on the scoreboard; it is only imprinted in the strides of the opponent, until the sixth game, when they stop. Friday will be the real test. Zverev, the top seed, or Van De Zandschulp, who has gone further than anyone predicted. If it is Zverev, Khachanov must face a player who serves better and returns more steadily than anyone he has met at Flushing Meadows this year. Then the lesson from the second set, the ability to hold rhythm in long service games, will be the only path. At twenty-nine, unseeded, reaching the third semifinal of a Grand Slam, Khachanov is answering a question this industry rarely has the patience to ask: how far can a quiet player go before he must make noise to be remembered?