Two weeks, two wins: Kostyuk beats Stephens again at US Open

New York, Arthur Ashe Stadium, late August. Marta Kostyuk had just finished her match with her eighth ace of the day — an unreturnable serve at the moment she was facing set point. She raised her hand, took a breath, then continued. Three games later, the match ended 6-1, 7-5. This was the second time in 15 days she had beaten Sloane Stephens, following a 7-5, 7-5 win in Cincinnati. But the most impressive number wasn't in the scoreline — it was the way she produced 30 winners, 20 more than her opponent, and 8 aces in a match where she had let slip a 6-1, 4-2 lead. The context of this match was not simply a first-round Grand Slam encounter. Stephens is the 2026 US Open champion, a player who knows how to win on this surface. Kostyuk, born in 2026, won the junior doubles title at Flushing Meadows in 2026 — the same year Stephens claimed the main title. The "full circle" narrative was heavily exploited by the media, but Kostyuk didn't care about that script. She said after the match: "I knew Stephens would try to change something. I was prepared for that." That statement reveals deliberate tactical preparation, not a lucky win. Looking at the data, the picture becomes clearer. Kostyuk has 34 match wins this season on the WTA Tour — a number in the leading group. She isn't just in good form; she is accumulating wins systematically. But what caught my attention wasn't the total number of wins, but how she handled pressure in this match. When Stephens began to adjust — dropping deeper to return serves, extending rallies — Kostyuk lost four straight games from 6-1, 4-2. That's the moment many young players collapse. She didn't. She saved set point with an unreturnable serve, then won the last three games to close out the match. Numbers tell half the story; the other half lies on the court. Kostyuk's 30 winners is an impressive figure, but it also reflects a high-risk style. She hits hard, hits deep, and accepts the trade-off. What the stats don't show is her unforced error count — which could be similarly high, as that's the nature of aggressive play. But in this match, she controlled the most important part: the crucial points. Saving set point, winning the last three games, and not letting the opponent drag the match into a deciding set. Three seasons I stayed silent, then the data spoke for itself. I've followed Kostyuk since her junior days. She always had good technique, but what makes her different at this stage is her maturity in reading the match. She doesn't just know how to hit hard; she knows when to hit hard. The match against Stephens is a prime example: after losing the lead, she didn't panic, but returned to the patterns that had given her the advantage. That's a sign of a player who knows how to self-adjust mid-match — a skill many young players take years to learn. There's a contrarian angle here that the media often misses. This win isn't just about Kostyuk. It also says something about Stephens — a Grand Slam champion in the late stage of her career, still dangerous enough to beat anyone on a good day, but no longer with the stamina to sustain pressure over three sets. Kostyuk knew that. She said she "knew Stephens would try to change something" — and she was right. Stephens did change, but not enough to turn the tide. This shows Kostyuk didn't just win with power, but with thorough tactical preparation. That pressing looked beautiful on the stats sheet, but fell apart on the court. I've seen too many young players have impressive first-round Grand Slam wins and then disappear in the second round. Kostyuk isn't like them. She has 34 wins this season, two consecutive wins over a Grand Slam champion, and an aggressive style suited to hard courts. But the big question remains: can she sustain this level against a Top-10 player, someone who can exploit her weaknesses — specifically, her inconsistency when opponents extend rallies? I don't believe in revolutions; I believe in accumulation. Kostyuk is accumulating steadily. Each win, each tournament, each moment of pressure is a new layer of sediment. This match showed she has taken another step in controlling emotions and maintaining focus. But professional tennis doesn't forgive complacency. If she lets this win distract her, she'll soon realize that every match starts from zero. Slow down one beat to read the match's rhythm. What I want to see from Kostyuk in the coming rounds is how she handles situations where her aggressive game no longer works. When opponents read her serve, when her big hits come back safely and deep, what will she do? In the match against Stephens, she had an answer: return to basics, hit deep, and wait for opportunities. That's a good sign. But Stephens is no longer at her peak. A player like Iga Swiatek or Aryna Sabalenka won't give her many chances to correct mistakes. The 2026-18 season taught me that pressing also needs humility. In football, I learned that constant pressure without adjustment leads to collapse. Tennis is the same. Kostyuk showed she can adjust — that's the most important thing. But she also needs to remember that 30 winners in one match isn't a sustainable standard. There will be days when she has only 15 winners and 25 unforced errors. On those days, she needs a Plan B. And what is her Plan B? That's a question I don't yet have an answer to. In football, what's forgotten is often what's most worth watching. In this match, what was forgotten is that Kostyuk saved set point with an unreturnable serve — a small detail that speaks volumes about her mentality. Not everyone can stay calm at that moment. She didn't just save set point; she won the last three games to close the match. That's a sign of a player who knows how to finish matches — a skill many technically gifted players lack. Looking ahead, Kostyuk will face a higher-ranked player in the second round. That's when the lessons from this match will be tested. Can she replicate the level of focus she showed in the last three games? Can she maintain a good first-serve percentage to set up aggressive shots? And most importantly: can she avoid the mid-match dip that happened when she led 6-1, 4-2? These questions will be answered in the coming days. But regardless of the outcome, this match has shown one thing: Kostyuk is no longer a promising young talent. She is becoming a real player, with wins based on data, tactics, and clear strategy. I will follow her in the coming rounds, not to see if she wins, but to see how she handles difficult situations. Because in tennis, as in life, people are not judged by what they do when things go well, but by how they react when things start going against them. Kostyuk showed a good version of herself in this match. The question is whether she can repeat it when the opponent is stronger, the pressure is greater, and the court is bigger. I'll be watching.