Stan Wawrinka can see the positives of his Australian Open run despite the bitter disappointment of losing to Swiss compatriot and close friend Roger Federer.

The No.4 seed survived a five-set scare from Slovakian Martin Klizan in the first round at Melbourne Park, but dropped just one more set on his way to Thursday’s semi-final with Federer.

On the back of last year’s US Open crown, Wawrinka had been aiming to become the first man other than Federer, Rafael Nadal or Novak Djokovic to win back-to-back grand slam titles since Andre Agassi in 1999-2000.

The three-time grand slam champion appeared headed for the final when he stormed back from two sets down before Federer’s fifth-set heroics dashed his hopes.

“I’m proud of myself, of the fight I gave (in the the semi-final) and all the tournament,” Wawrinka said.

“There is a lot of positives from this tournament, from Brisbane, from the month already.

“For sure I’m really sad and disappointed with a loss like that because to be that close to have won a semi-final, it can be only sad.

“But at the end I had a great battle against Roger. He’s a great fighter. He’s always been amazing in grand slams, in five-set matches. I’m for sure sad to lose a match like that.

“But I know there are a lot of positives.”

Wawrinka’s optimism for the season ahead is tempered by concern over a knee injury he carried throughout the Open.

“It’s been an issue since the beginning of the tournament … (but) it’s not an excuse at all,” the 31-year-old said.

“I go on the court with what I have on the day. I give everything. (But) what exact (injury) I have, I have to check. Really I have to do some bigger tests when I get home.”