Novak Djokovic, of Serbia, gestures to the crowd after he lost to Mariano Navone, of Argentina, during the first round of the U.S. Open tennis championships Sunday, Aug. 30, 2026, in New York. (AP Photo/Frank Franklin II)Seven of the men’s top 10 seeds are gone from the US Open after eight days. Stretch that to the top 20, and it’s 15.Djokovic started it. Medvedev kept it going. Most of the upsets share a strange helplessness, players who can’t quite explain what happened to them.Djokovic “despised every moment” against Mariano Navone. Arthur Fils was up 5-2 in the second set on Stefanos Tsitsipas when his energy simply left him, no explanation, just gone, a lapse he called “almost unprofessional.”Alex de Minaur had a favourable draw on paper and lost anyway, in the second round, to Botic van de Zandschulp. “I can’t really explain the reasoning of it, but it just felt like the more I tried, the more intensity, the more fired up I was getting, I just kept on making unforced errors,” he said. The feel of the ball on the strings, gone, and he couldn’t get it back.Felix Auger-Aliassime got dizzy against Karen Khachanov. Started seeing spots after a set and a half. Never recovered. “I thought maybe it would pass, but it didn’t,” the No. 3 seed said. “I’ve never felt quite like that. I’ve had cramps before. I’ve felt tired towards the end of matches, but in a normal way. This was abnormal a little bit.” He finished with 47 unforced errors.Taylor Fritz led Francisco Cerundolo by two sets and a break. Then it fell apart. “I don’t even know what to say. I don’t really want to talk to anybody, see anybody,” he said. “I need to get out for a couple days and then get back to work. I don’t know how I let that happen today.”Packed calendarFlavio Cobolli, fifth seed, lost to Alexander Blockx and pointed to fatigue. “I think my energy was a little bit lower than the other days,” he said. “I feel a little bit more tight and maybe more tired.”Story continues below this adHe’s not alone. Carlos Alcaraz, back from a four-month wrist injury, has already been vocal about how packed the calendar has become. Jannik Sinner and Casper Ruud withdrew injured before the tournament even started. The shocks at Flushing Meadows may share a root cause: an expanded ATP schedule, and a modern game that already demands more of the body than most seasons allow it to give.Blockx, the man who beat Cobolli, put it plainly. “The season is long. I think all the guys who performed well in the preparation tournaments have it more difficult here,” he said. “We’re all human. We’re not robots. Every week is difficult. Especially at a Grand Slam where it gets even more physical. Mentally you have to really stay in it.”Open fieldCredit where it’s due, the players pulling off these upsets are also grinding through a brutal tour, and their run through the first four rounds has cracked the men’s draw wide open. The women’s side tells the opposite story: 11 of the top 16 seeds are already through to the fourth round.Cerundolo, fresh off his comeback win over Fritz, called it a reflection of how tight the circuit has become. “It shows you how even the circuit is right now, how tight every match is, how difficult it is to win matches, because anything can happen right now,” he said. “A lot of players are playing good. The level, it’s super tight. It’s open to everyone. Everyone can win.”Story continues below this adAlcaraz and top seed Alexander Zverev remain the favourites, upsets or no upsets. Alcaraz is playing his first tournament back from injury and has looked confident through four rounds regardless. He and Sinner have shared 10 of the last 11 major titles between them, a stranglehold that’s tormented everyone else on tour; Zverev is the one man who broke it, and he knows exactly how hard that was to do. He’s admitted nerves once kept him from sleeping or eating properly before earlier Slams, and even after finally breaking through at Roland Garros and reaching the Wimbledon final, his best tennis still wasn’t enough to unsettle a fully fit Sinner.Alcaraz looms again this time. If both he and Zverev play to their pedigree, New York could get the final it seems built for. Unless the upsets keep coming through the quarters and semis, and someone like Ben Shelton, Frances Tiafoe or Learner Tien takes the title instead.That might not be such a bad thing for the sport.