Two weeks, two wins: Kostyuk repeats script to beat Stephens again at US Open

New York, Tuesday night – As the clock ticked into the ninth game of the second set, Marta Kostyuk stood at the baseline, glancing toward her bench. She had just let Sloane Stephens level at 4-4 after leading 6-1, 4-2. An easy set win was nearly gone. But instead of letting the memory of that U23 Asian Cup final in Changzhou – where I learned that there are heartbeats that echo far without goals – take over, Kostyuk did what great players do: she kept the rhythm. Her eighth ace of the match – an unreturnable serve at set point – carried her to a 6-1, 7-5 victory over the 2026 US Open champion. Three straight games to close out the match. No third set. No dramatic comeback. Just a clean, decisive finish at exactly the right moment. This is the second time in 15 days Kostyuk has beaten Stephens. In Cincinnati, she won 7-5, 7-5. At Flushing Meadows, the scoreline was even more lopsided in the first set. Two weeks, two wins, same opponent – a former Grand Slam champion, a player who won this very title when Kostyuk was a junior doubles champion on these same courts. When the stands fall silent, I listen to the court through xG and find that data can also vibrate. In tennis, the equivalent of xG is the winner and ace count. Kostyuk had 8 aces and 30 winners – 20 more than Stephens. This wasn't a match. It was a controlled domination. But the real story isn't in the dry statistics. It's in how Kostyuk handled the moment when everything started slipping away. She led 6-1, 4-2. Then Stephens, a Grand Slam champion, began hitting deeper, extending rallies, forcing Kostyuk to hit one more ball, then one more. The lead evaporated. The second set returned to equilibrium. I've watched enough of Stephens to know that when she starts moving well and hitting deep returns, she becomes one of the most frustrating defensive players on tour. But Kostyuk was prepared for it. "I knew Stephens would try to change something," she said afterward. "I just needed to hold my ground." That's a statement of tactical maturity rarely seen in a 22-year-old. She didn't panic when the initial plan was disrupted. She waited, adjusted, and struck back exactly when Stephens began to lose rhythm. The number 34 – Kostyuk's win total on the WTA Tour this season – is a remarkable figure. It places her among the tour's win leaders, a position usually reserved for top-10 names. But what makes this number more meaningful is how it was built: not just by beating lower-ranked players, but by defeating former Grand Slam champions in consecutive weeks. Fans don't need golden trophies; they need a reason to sing together on the streets. For Ukrainian tennis fans, Kostyuk is giving them a reason. She's not just a rising young player – she's a warrior representing a nation at war. Every Grand Slam victory she earns is a message that transcends the court. But let's talk about the contrarian angle. Losing a 6-1, 4-2 lead isn't a sign of weakness – it's evidence that Kostyuk still has a gap to close. Her winner-based attacking game has a downside: when opponents adjust and extend rallies, her unforced error rate can spike. Stephens found a way to exploit that for about 20 minutes in the middle of the second set. If a more disciplined defensive player – someone who doesn't make errors and forces her to hit one more ball – can exploit this weakness for longer, Kostyuk will be in serious trouble. That's why I'm not rushing to call her a title contender. Beating Stephens is a positive signal, but Stephens is no longer at her peak. The real test will come in the third or fourth round, when Kostyuk faces a top-10 player – someone who can serve as well as she does and hit winners as often. The "full circle" narrative – she won junior doubles here when Stephens won the main title – is great media material. It adds a layer of drama to the match and gives my article emotional depth. But it doesn't directly translate into going deeper in the tournament. The beauty of a story doesn't beat a 180 km/h serve from a top-10 player. What I really want to watch is how Kostyuk handles her next match. Can she re-establish her attacking rhythm from the start, or will she again let her opponent catch up before finding a way out? Her ability to keep rhythm – what I call "keeping the beat" – will determine how far she goes in this tournament. There's a small detail I noticed: when Kostyuk saved set point with an unreturnable serve, she didn't scream or over-celebrate. She just nodded, walked to her chair, and prepared for the next game. That's a sign of a player who has learned to control emotions in crucial moments. At 22, with 34 wins this year, she's entering the most mature phase of her career. Stephens, at 30, is on the other side of the age curve. She can still play great matches, but her ability to sustain form over multiple rounds is declining. This loss might be another chapter in the "former champion exits the stage" story – a story I've witnessed many times in my journalism career. But for Kostyuk, this is just the beginning. The question isn't whether she can beat a former Grand Slam champion – she just did it twice in two weeks. The question is whether she can beat a current champion. That's the next leap, and it will come sooner than she thinks. As I left the press area that night, I remembered a phrase I once wrote in a football analysis: "optimism index." Fans are always optimistic before every expectation, but data is what keeps the rhythm. Kostyuk has data on her side: 8 aces, 30 winners, 34 wins. But the data also shows she nearly dropped a set she led 4-2. The truth lies in between: she's a talented player learning to become consistent. And that's exactly what makes her worth watching in this tournament.