Laura Robson toed the baseline, then vaulted into her serving motion. The ball landed five feet behind the line.
Moments later, she bounced her second serve into the net.
Those were the ugliest of the ugly for the British 19-year-old on Monday at Wimbledon and they couldn't have come at a worse time.
The double fault turned what had been a 5-2 lead in the first-set tiebreaker into a 5-all tie.
Four points later, Kaia Kanepi had won that tiebreaker, and about 45 minutes after that, Robson was heading off the court, nearly in tears.
Robson failed in her quest to become the first British woman to reach the Wimbledon quarterfinals since 1984, falling 7-6 (6), 7-5 in a jittery, error-filled match against an opponent who has been in these spots before.
"I was putting a lot of pressure on myself," Robson said. "At the end of the first set, I had my chances. I served for it. In the tiebreak, as well. At that point, I was just trying to will myself to play unbelievable tennis when, you know, just making a serve would have been fine."
The first British woman to reach the second week of Wimbledon since 1998, Robson was the subject of a tweet from Prime Minister David Cameron, who wished her luck.
Notable among the packed crowd on Court 1 were the hundreds of girls who had come to see the woman who might someday be the country's top tennis star.
Though hardly in the same fishbowl as Andy Murray, who is trying to end a 77-year British drought for the men at Wimbledon, Robson also has the eyes of her nation upon her.
She insists she tries to tune it out. But, she concedes, this trip to the round of 16 felt much different than last year's trip to the same spot at the U.S. Open.
In part because she's been playing well.
In part because it's Wimbledon.
"U.S. Open last year, I was just kind of like happy to be there," Robson said. "Today, I went out and I really thought I had a chance of winning. I was feeling confident going into the match."
It didn't show. Not after she broke for a 5-4 lead in the first set, then gave the game back, starting with a double fault, then spraying a pair of forehands long.
And not during the tiebreaker, when she saw that 5-2 lead turn into an 8-6 loss, capping it with two more unforced errors to close the set.
Robson finished with 24 unforced errors versus only 27 winners, as she had trouble harnessing the forehand that has served her well over the past year, during which she has vaulted from the 120s to 38th in the rankings.
Kanepi, ranked 46th, moves into her fifth Grand Slam quarterfinal.
Jo Durie stays as the last British woman to make the Wimbledon quarters, 29 years ago.
And Robson remains Britain's next great hope on the women's side.
She's the one they came to watch on Court 1 on Monday. But as she collected her gear and made her way toward the exit to the extended applause, she kept her eyes straight ahead and didn't even offer a wave.
"Because I lost," she said, "and I was just trying not to cry."