NEW YORK -- Andy Murray came into this fortnight with more matches played than anyone on the ATP World Tour this season.
When he left Monday night, after a superb 7-0 fourth-set tiebreaker from South African Kevin Anderson, the 28-year-old Scot looked exceptionally weary.
"I felt like I was able to fight as I wanted to through to the end of the match," Murray said in his postmatch news conference. "So I don't think the amount of tennis I played played a part.
"It was more playing against Kevin on the court of that speed, and with him serving as well as he does, it's a tricky match. It comes down to a few points in each set. He managed to get them today."
A succinct appraisal -- and an accurate one.
Anderson won 7-6 (5), 6-3, 6-7 (2), 7-6 (0) in the tournament's longest match, which lasted 4 hours, 18 minutes. Murray had previously lost only one 7-0 tiebreaker.
This match dramatically changed a long-standing karma for both of these players.
The 29-year-old Anderson, in his ninth year as a professional, had been to the fourth round of a Grand Slam seven times but has never reached the quarterfinals. Now he has.
Murray, on the other hand, had previously reached the quarterfinals of the 18 consecutive Grand Slam tournaments he had played, a remarkable record of consistency over five full seasons.
Afterward, he was asked about that telling statistic.
"Yeah, well, that's obviously something that is disappointing to lose because of that," Murray said. "Obviously that's many years' work that's gone into building that sort of consistency. To lose that is tough.
"Also to lose a match like that that was over four hours, tough obviously after a couple of tough matches earlier in the tournament, as well, it's a hard one to lose, for sure."
Anderson, who is generally impassive on the court, actually showed some emotion, dropping in a rare fist pump late in the third set after a spectacular pass of Murray.
"I'm a little lost for words," Anderson said in his on-court interview. "I just managed to keep my composure and, honestly, played one of the best matches of my life."
Murray said the swift speed of the court on Louis Armstrong Stadium complemented Anderson's big game that produced 25 aces.
"That court is a lot quicker than [Arthur] Ashe," Murray said. "I felt like I was on the back foot quite a lot. Wasn't able to play that offensively."
That's not a bad description of his game over the past two years, the aftermath of his greatest victory ever, at Wimbledon in 2013.
He has made nearly $10 million the past two seasons and won seven titles, but none of them qualify as major victories -- which is how a player of Murray's skill measures himself against his peers.
Murray entered the match with a 59-9 record and had won four titles -- two on clay, in Munich and Madrid, one on grass at Queen's Club and last month in on the hardcourts of Montreal. Murray beat Novak Djokovic in that final, and the result suggested Murray might be ready to make an impression in New York.
When he looks back, this will probably be Murray's most disappointing effort in the Grand Slams this year. He lost to Djokovic in the finals at Melbourne and the semifinals at Roland Garros. At Wimbledon, he fell in the semifinals to Roger Federer.
Part of the problem has been some flux in Murray's coaching situation. He had lost four Grand Slam singles finals when he finally broke through with a victory here in 2012. He followed that up the next year with a celebrated triumph at Wimbledon. The constant was coach Ivan Lendl.
It was Lendl, the eight-time Grand Slam champion, who finally convinced Murray to jettison his safe, centered play and start going for lines when the points really mattered. That belief carried Murray to the Olympic gold medal at London and, not soon after, the US Open title. Since that Wimbledon championship, Murray is 0-for-9 in majors.
It may not be a coincidence Lendl left his post as Murray's coach early last year.
"Working with Andy was great," Lendl said a little more than a year ago in New Haven, Connecticut. "He found the belief that he could win matches by going for it. We had a great run.
"I hope he can keep it going."
The belief, however, seems to have waned.
Two-time Grand Slam champion Amelie Mauresmo became Murray's coach last June, marking a milestone. No woman had ever coached a top-ranked man. Reportedly they get along well, discussing world events and drinking red wine with dinner. When Mauresmo recently took a maternity leave, former Swedish player Jonas Bjorkman has taken a seat in the coaching box.
That's three coaches in two seasons.
Fortunately for Murray, there is a yawning distraction in the offing. Great Britain hosts Australia in the Davis Cup semifinals on Sept 18-20 in Glasgow, Scotland.
For Murray, it probably can't come fast enough.
"Yeah. I'm looking forward to the tie, yeah," Murray said.
"But right now I'm not thinking about that."