Melbourne - Stan Wawrinka admitted on Wednesday he ran out of steam in his Australian Open quarter-final after a gruelling tournament, but is taking a lot of positives out of the first Grand Slam of the year.
The veteran Swiss crashed out in the last eight to German young gun Alexander Zverev, unable to maintain a blistering start as he lost 1-6, 6-3, 6-4, 6-2.
"I think after one set and a half, for sure, I was going a bit down physically. Also lack of energy," he said. "But he was playing well, was serving big. I think I could have done better in the second and the third set."
The three-time Grand Slam champion - a winner at Melbourne Park in 2014 - came into the match after a tough five-set win over fourth seed Daniil Medvedev.
That followed another five-setter in round two against Andreas Seppi, and they appeared to take their toll on the 34-year-old.
"In the end, if I look at the third set and fourth set, I was struggling to really push myself. It was not enough," he said.
Despite failing to make his first Slam semi-final since his run to the French Open final in 2017, Wawrinka was happy to again reach the second week of a Major, which he said set him up well for the season.
"In general I'm happy with the tournament. I had a really difficult first week. I had to fight a lot to still be here," he said.
"I'm happy to make quarters again, happy to see the level I have, the way I'm playing."
"I'm positive I will come back next year," he added.
Wawrinka has not won a title since pocketing the 16th of his career on the Geneva clay in 2017, with two bouts of surgery on his left knee that year pushing him to the brink of retirement.
A lengthy absence from the tour meant his world ranking plunged, but he has climbed back to world No 15 after runs last year to the quarter-finals at Roland Garros and the US Open.
Results on day 10 of the Australian Open Grand Slam at Melbourne Park on Wednesday (x denotes seeding):
Alexander Zverev (GER x7) bt Stan Wawrinka (SUI x15) 1-6, 6-3, 6-4, 6-2
Simona Halep (ROM x4) bt Anett Kontaveit (EST x28) 6-1, 6-1
Garbine Muguruza (ESP) bt Anastasia Pavlyuchenkova (RUS x30) 7-5, 6-3