There would be no valiant comeback from a two-set deficit for Andy Murray this time.
His weary body -- and the Canadian on the other side of the net -- wouldn't allow it.
Murray, the three-time Grand Slam champion still working his way back from a pair of hip operations, was beaten by Felix Auger-Aliassime 6-2, 6-3, 6-4 in the second round of the US Open on Thursday.
"I need to build up my body and my conditioning," Murray said.
The 15th-seeded Auger-Aliassime dominated throughout, compiling a 52-9 edge in total winners, including 24 aces, and taking 41 of the 46 points when he put his first serve in play.
Perhaps even more notably, Auger-Aliassime never faced a break point against Murray, one of the game's great returners.
It was too much to ask of Murray, a 33-year-old with a metal hip who two days earlier toiled for 4 hours, 39 minutes while building his 10th career comeback from two sets down to beat Yoshihito Nishioka 4-6, 4-6, 7-6 (5), 7-6 (4), 6-4.
Auger-Aliassime sat in his player suite for part of that match and was aware Thursday that he shouldn't feel too confident despite his big lead.
"In the back of your mind, you know you're facing Andy Murray," Auger-Aliassime said. "You never know what tricks he's got in his pocket."
Tuesday marked Murray's first Grand Slam match in nearly 20 months. He thought his problematic hip would force him to retire in 2019, but he made it back to the tour.
"The more tournaments you play, the more matches you play, the more you build up the robustness in your body, which I don't really have," Murray said. "Look, definitely tennis-wise could be better, as well. I feel like I played some good stuff at times, but it was quite up and down."
Murray, a former No. 1-ranked player whose résumé includes two Wimbledon championships and two Olympic singles gold medals, said he is uncertain about playing in the French Open at the end of the month and won't be playing in the clay-court warm-up in Rome. But he was hopeful about his ability to continue to compete at the highest level.
"I would say even after tonight, like, I would say I'm more positive about what I could do in Grand Slams than I was before I came over here," he said. "You guys obviously don't know how I was feeling even just a couple of months ago.
"In terms of winning Grand Slams again, that's going to be extremely difficult to do. It was hard enough when I had two normal hips. So it will be difficult, but I'll keep trying, like, why not? Why shouldn't I try my hardest to do that? And if I don't, that's all right. But I might as well shoot for the stars. And if I don't -- yeah, if I don't get there, then that's all right. But I'm trying my best to get the most out of what my body gives me now."
Auger-Aliassime, who turned 20 last month, is considered one of the up-and-coming stars of men's tennis. He joins No. 12 seed Denis Shapovalov and unseeded Vasek Pospisil to give Canada three men in the third round of a Grand Slam tournament for the first time, according to the ATP.
Auger-Aliassime's next opponent will be No. 23 Daniel Evans of Britain or Corentin Moutet of France. Their match was suspended in the third set because of rain Thursday and will resume Friday.
Also Thursday, third-seeded Daniil Medvedev beat Australian Christopher O'Connell 6-3, 6-2, 6-4 to advance to the third round.
Medvedev, who is into the third round for the third straight year, was the 2019 runner-up. Last year, the crowd turned on him, and he relished his role as the tournament villain, taunting fans after wins.
He said Thursday that it was "sad" to play a night session without fans.
Earlier Thursday, second-seeded Dominic Thiem earned a spot in the third round with a 6-3, 6-3, 6-1 win over Sumit Nagal.
Thiem, who turned 27 on Thursday, faces 2014 US Open champion Marin Cilic in the next round.
No. 8 Roberto Bautista Agut, No. 11 Karen Khachanov and unseeded Americans Frances Tiafoe and J.J. Wolf also advanced. No. 14 Grigor Dimitrov and No. 25 Milos Raonic were eliminated.
The Associated Press contributed to this report.