Tom Rogic is looking to put a "nightmare" 12 months behind him and prove himself at Celtic.
Injury has hampered the 22-year-old Australian midfielder's progress and he has made 15 appearances since signing from Central Coast Mariners in 2013.
"It was a bit of a nightmare," said Rogic. "I don't want to get into it too much. I had a serious groin injury.
"I feel I've come out the other side of that. It was a pretty testing time. I never thought it would be as long."
Rogic has only started five times in competitive action for Celtic but has featured in Ronny Deila's line-ups against Den Bosch and Dukla Prague in pre-season friendlies.
Starting against the Czechs came despite the return of nine players who had been given extra time off because of international duty.
"It's hard to put into words, it was pretty difficult," said Rogic, who spent six months back in Australia on loan with Melbourne Victory in the first half of last year in an attempt to find match fitness.
"But that's past me now. I just want to be positive and look to the future."
"It's good to get games. I'm just happy to be out there.
"It's enjoyable and I just want to build on it. I'm feeling really good."
Rogic will use the experience of Nir Bitton as inspiration, the Israel midfielder having become a key player last season after taking time to adapt to the Scottish game.
"We came to the club at similar times," said the Australian.
"Nir had a bit of a slow start and proved with a run of games what a quality player he is. So, of course, I take confidence from that."
Celtic were beaten 5-3 by the Czech side at St Mirren Park, but Rogic feels the Glasgow side can quickly improve ahead of the Champions League qualifiers.
"They made it tough for us, but we were too open and we need to be better," added Rogic.
"It's only the second game of pre-season and for most of the lads starting it was their first.
"There is always going to be a bit of rust, so I don't think it's anything too serious to worry about."