MARANA, Ariz. -- Perhaps it was when he was first able to take a full swing. Or maybe it came when he unleashed his driver for the first time. Or it could be that it was the simple act of finally being able to get out of bed without his leg feeling like it was going to explode.
Then again, maybe it won't occur until Wednesday, when Tiger Woods steps between the ropes at the WGC-Accenture Match Play Championship at the Ritz-Carlton Golf Club, where he will play a tournament for the first time since knee surgery.
"Every athlete that comes back from injury has mental hurdles that they need to overcome," said Hank Haney, Woods' swing coach. "Tiger is no different in that regard. Having said that, I can't think of anyone in the world that is better at overcoming a mental hurdle than Tiger."
If there was a "mental moment" to get past, a point in time when Woods faced fear about his comeback and overcame it, he has yet to say.
But you could undoubtedly look at some significant milestones along the way.
The first one might have been the simple act of walking without pain.
"I wanted improvement right away," Woods said of the time after his June 24 surgery to replace the anterior cruciate ligament in his left knee. "The first few months. Anyone that's ever dealt with an ACL [knows], it's just brutal. You lose all your muscle. You lose your flexibility. You lose all your endurance. It's just a terrible feeling.
"But then building that up, it came back quickly. I'm very fortunate that I do play golf. We can conceivably play competitively into our early 50s. You certainly can't do that in basketball. I can understand why other athletes in other sports push it and try to come back earlier or try to stay on the court or the field as long as they possibly can because you just don't know about your timetable when that window closes."
Although he defied doctors' orders by playing the U.S. Open, Woods has seemingly followed their advice since his surgery to replace the ACL.
He was told not to rotate on the knee for six months, and while Woods did begin hitting balls in December, he said he remained careful and worked mostly on his short game.
"I saw him hit some balls in the winter when he was in California, and he was barely getting into full swings, so he was a little hesitant," said Champions Tour player John Cook, a friend and neighbor of Woods who frequently plays golf with him at their home course, Isleworth, in Florida. "[It was] 75 percent, maybe, speed-wise. Then he'd test it, then he'd just go back to hitting nice shots, controlled shots."
That changed sometime in January, when Woods began to work through all the clubs in his bag.
Cook, an 11-time PGA Tour winner, said he played with Woods several times two weeks ago, and that "was the first time I'd seen full barrel, full swing, full speed," he said. "I was pretty amazed, that the quality came back so quickly."
ESPN golf analyst Andy North knows a bit about returning from knee surgery. He endured it five times during his playing career, which saw him win two U.S. Opens. Undoubtedly, North said, Woods faced trepidation at some point in this comeback process.
"That's basically the story for anybody coming off a surgery," North said. "His left knee was a mess for a while, and he never really said anything about it. It's probably more stable now than since he was in college. You have to trust it; that's the hard thing.
"But you know he's worked out harder than anybody. And once you make that big swing and it works OK and you get some confidence, then you're OK. Then when you're tired, and you do it, you should be OK. The biggest thing most people don't do is they don't get strong enough before they come back."
Woods has reported that his legs are stronger than ever, that the knee feels fine, that he could have actually returned to competitive golf sooner than this week's World Golf Championship event.
The birth of his son, Charlie, on Feb. 8 prevented that, and Woods said he first wanted to make sure all was well with his family before teeing it up again.
Meanwhile, he kept working on his game, saying he played or practiced nearly every day.
"He's tested it; he's tested it all day, and his recovery time the next day has been fine," Cook said. "I don't see him favoring anything. I know that he has put the hammer down a couple of times and hit that 'I'm going to drive the 16th green [a par-4] at Doral' swing. No effect.
"And he never lost the short game. That's what the amazing thing was to me, seeing some of the pitch shots that he was hitting at Isleworth. You get some funky pitch shots there, and nobody's better than that still. No rust on the short game.
"The only real variables are how will you be able to walk and play and get into golf shape. He's in phenomenal shape physically. His golf game is as good and as consistent as ever. [But] competitively, it's been eight months. I don't care who you are, you just don't come back out and get into that walking, playing mode, being competitive where you have to putt out every single putt."
While Woods said his goals remain unchanged -- to try to compete and win -- he did acknowledge that he is curious, just like everyone else.
Will there be rust? Will there be tentativeness to go after a driver when he needs it? Will there be any indecision on the greens?
"I'm looking forward to the challenge of doing that," Woods said. "I haven't been out there. Haven't really been able to test it in a competitive environment yet. What I do at home yeah, I do feel good. I'm able to hit all the shots. It's just a matter of getting out there and performing in a tournament and dealing with the pressures of the tournament. That is something that I haven't done in a while."
Bob Harig covers golf for ESPN.com. He can be reached at BobHarig@gmail.com.