A proud Nick Kyrgios is targeting improved physicality and mentality after his Australian Open quarter-final exit on Tuesday.

The Australian, 19, was outclassed in a 6-3 7-6 (7-5) 6-3 loss to British sixth seed Andy Murray on Rod Laver Arena.

Kyrgios was in some doubt for the year's first grand slam due to a back injury, but put the problem aside to reach the last eight.

He has identified aspects of his game to work on, including maintaining concentration.

"I was hurting out there, so physicality is a big one," Kyrgios told a media conference.

"My mentality, I thought I had a couple dips out there. I need to stay consistent.

"But just in general, the forehand return, I didn't think I was getting on his serves tonight. I thought he served really well, a lot of variety.

"I thought if I could get that second set it's a totally different match, but, you know, he won the second set and he was too good."

Kyrgios will rise from his ranking of 53 and somewhere into the world's top 40.

While he believes pushing into the top 20 in the world is reachable, his goal is simply to stay fit.

"I wouldn't put a number on it. I think one of my goals is just to stay healthy," Kyrgios said.

"I just want to stay on the court and obviously do what I love to do out there: play.

"I think that's my main goal with me and my team, keep me on the court for as long as possible this year."