Stan Wawrinka admits he was on the verge of pulling out of the Australian Open before a last-minute hitout convinced him to return from his six-month injury layoff.
The triple grand slam champion hasn't played since undergoing surgery on his injured knee following a first round defeat at Wimbledon.
Speculation about his fitness intensified after he pulled out of Wednesday's Tie Break Tens fast-format exhibition event at Melbourne Park.
With his first match scheduled for Tuesday, Wawrinka has revealed he was undecided about committing to the Australian Open until he got through a practice session on Saturday.
"It's the most important for me to be careful with the knee. That's why I waited (until) the last minute to decide if I was going to play or not," he said.
"There's always a little risk, for sure, especially starting after six months in a match, you going to get more tight, you going to get nervous, you're not going to feel as comfortable in a match as in practice.
"But the knee is staying there, so that's the most important."
The 2014 Australian Open champion tempered expectations of a deep run this time around after such a long layoff, adding that his knee was still causing him pain.
Wawrinka instead hopes to use the opening grand slam of the year as an opportunity to push himself back into competition and test his fitness in the five-set format.
"The knee is getting way better (but) I still have a lot of work to do physically and also tennis-wise to be to my top level," he said.
"I'm going to take the time I need for that.
"It's a good place to start, to get pushed, to see also mentally how I'm going to react, how I'm going to feel when I'm going to be playing matches."
Wawrinka will open his campaign against Lithuanian world No.138 Ricardas Berankis.
The Swiss ninth seed has been drawn in the same quarter as world No.5 Dominic Thiem and Roberto Bautista Agut.