Thanasi Kokkinakis admits he was ready to quit tennis just two weeks after beating Roger Federer, fearing a freak knee injury had left him with a ruptured anterior cruciate ligament.
The 22-year-old South Australian, who's battled a catalogue of injuries over the last three years, looked set for another long lay-off after crashing into a sponsors sign during at match at the Monte Carlo Masters in April.
It was initially thought the former world No.69 had badly bruised his kneecap but a doctor insisted he go for scans after refusing to rule out any significant damage.
However, the results came back negative and Kokkinakis said he wouldn't have been able to mentally cope with the prospect of another long stint on the sidelines.
"Every time I freak out a little bit and when they tested me for an ACL ... well I thought that was me done," Kokkinakis said at the Surbiton Trophy Challenger Tour event in London.
"They were fearing the worst, and so was I to be honest given my injury history, because it swelled up so much.
"I would have pulled the pin for sure. For a couple of years at least. I would have probably only come back if I was bored.
"But thankfully it came back all clear and I just need to keep fit now.
"I know what my top level is but I also know what my bottom level is and I need to make sure I am closer to the top."
Kokkinakis, who nine weeks ago became only the second man to lower Federer's colours this year, demonstrated his inconsistent nature in Surbiton on Tuesday by losing to Indian world No.93 Yuki Bhambri.
The world No.148 went down 6-4 7-6 (7-4) in a dispiriting display in southwest London.
He'll now travel to The Netherlands to try and qualify for the Libema Open grass court event ahead of Queens Club and Wimbledon - which will also require him to battle through qualifiers.
The affable Kokkinakis - one of the most popular players on the ATP tour - admits he needs his brittle body to stand up to the rigours of elite tennis now more than ever if he's to ever fulfill his rich potential.
"It's tough, I have been struggling to find my motivation as I've been in a cycle of rehab for so long," he said.
"When I am out there playing, sometimes I'm into it and sometimes I am not where I need to be.
"When I beat Federer that was when I had a complete run at it. I played four successive tournaments for the first time in a long, long time.
"Hard and clay are my best surface but I beat (Milos) Raonic at Queens last year so I can do well on grass too."
Jordan Thompson, a finalist at this event last year, also succumbed to an Indian player, going down in three sets to world No.123 Ramkumar Ramanathan.
