Bernard Tomic was pleased with his ability to stay with Jarkko Nieminen while the Finn was on top in their quarter-final at the Sydney International.
The 20-year-old Australian took control of the match from midway in the second set to record a 6-7 (6-8) 6-4 6-2 win in one hour and 51 minutes on Thursday.
But world No.44 and defending champion Nieminen had him battling, and Tomic was delighted he managed to stay in touch despite not being at his best.
"I was happy with myself to stay in there," Tomic said after his victory.
"I was very concerned after that first set."
Tomic has beaten Marinko Matosevic, Florian Mayer and now Nieminen on his way to the last four, where he will face Italian third seed Andreas Seppi.
Either Kevin Anderson or Julien Benneteau await Tomic if he reaches what would be his first ATP World Tour final.
Tomic, who reached the Wimbledon quarter-finals in 2011, said he was focused and full of confidence ahead of his meeting with Seppi.
"I'm ready to go for tomorrow's semi-final," Tomic said.
"I'm really confident now and I got a shot to get into the final for the first time in my career.
"The next match is a big match and I'm going to do everything I can to win tomorrow.
"To get the chance to play my first tour event final and to do it in Australia is going to be unbelievable, but I've got to play two quality players to do so."
Despite needing almost two hours to overcome Nieminen, Tomic dismissed any concerns he was tiring.
"I'm confident now. It's really good to win a match like this. Physically-wise I'm still pretty good," he said.