In the fourth round, Karatsev stormed back from two sets down to defeat Canada’s Felix Auger-Aliassime, the No. 20 seed, 3-6, 1-6, 6-3, 6-3, 6-4. Auger-Aliassime is one of the world’s top young players and looked as if he would easily handle Karatsev after the first two sets.
Then Karatsev took a bathroom break. He used the toilet and splashed some water on his face; and when he returned to the court, he found his comfort zone. He began firing aces and winners on his serve with abandon and pushed Auger-Aliassime farther and farther back into the court with his deep groundstrokes.
Karatsev looked to be following a similar script on a warm, humid Tuesday afternoon.
“I was a bit nervous at the start,” he said.
The nerves were certainly justified, but the court he was playing on had an unlikely resemblance to the countless courts where he has competed for years in lower-tier events in front of rows of empty bleachers. On Friday night, health officials instituted a five-day lockdown after more than a dozen people tested positive for Covid-19. There were no spectators other than a few journalists, tournament employees and the players’ support teams.
No one other than Dimitrov and the few people around him knew that he was taking the court at less than 100 percent. Dimitrov, one of the most talented and physically gifted players on the tour, had breezed through his first four matches, including his three-set dismantling of Dominic Thiem, the No. 3 seed.
Karatsev’s nerves showed in the first set, when he made 19 unforced errors and double-faulted three times. In the second set, though, he started standing toe to toe with Dimitrov, playing longer points, sending balls deep into the court and forcing Dimitrov to exert himself and put stress on his back. By the end of the third set, Dimitrov could barely stand.
Less than an hour later, Karatsev was in the semifinals.
“I’m trying to enjoy the moment, not thinking about it too much, just playing from round to round,” he said.