Beaten semi-finalists Stan Wawrinka revealed he was struggling with fatigue after his Australian Open loss to Novak Djokovic.
Stan Wawrinka described himself as "completely mentally dead" after his Australian Open semi-final loss to Novak Djokovic on Friday.
The Swiss defending champion went down 7-6 (7-1) 3-6 6-4 4-6 6-0 to the world number one in three and a half hours 30 at Rod Laver Arena.
Wawrinka helped Switzerland lift the Davis Cup in late November before starting 2015 by winning the Chennai Open.
And the 29-year-old believes those exploits caught up with him in Melbourne.
"Again, I think I'm physically well, playing well in general, really happy with my level," Wawrinka told a media conference.
"It was mentally that I think I'm paying off the price to finish off the season with Davis Cup, not having a bigger off-season, trying to focus really well to start well the year with winning Chennai and being here trying to do the best.
"I told my coach before the match and already yesterday that I was mentally completely dead and no battery.
"[It was] tough to focus on what I want to do, tough to focus on my game. And that's what happened today."
Wawrinka described the match as "strange" and "not the best" after he and Djokovic made 118 unforced errors between them.
And he lamented missed opportunities, including break points in the first and fifth games of the deciding set.
"[I] had few moments in the match that I could have take a little bit advantage in the game. I had the feeling that I was playing well," Wawrinka said.
"But, again, as I say, it's tough for me to focus on what I wanted to do.
"In third set I had break point. I should have broken the first game. I had easy an backhand that I missed. In the fifth - the same.
"With the wind, I had again chance to take advantage, but I was surprised that I came back in the fourth.
"I was telling my box it was tough for me to stay with him, to find a way to win points.
"Because I was just trying to fight and to make some good choice, but today I was just not there."