Wayde van Niekerk's biggest battle right now is taking place inside of him - his perfectionist mind against his flawed body.
He's the 400m king and the only man on the planet to have broken 10 seconds in the 100m, 20 in the 200m and 44 in the 400m.
Van Niekerk, 26, is the reigning Olympic champion from Rio 2016 and the two-time world champion from 2015 and 2017.
These accomplishments are engraved on his mind and muscle memory, but now he must factor in his reconstructed right knee.
Van Niekerk is already eyeing nothing less than first place at the 2019 edition of the World Championships in Doha where he will bid to join an exclusive club of greats to win three consecutive titles in the same event, like Usain Bolt, Hicham El Guerrouj, Haile Gebrselassie and Michael Johnson.
"I've felt gold so I don't want to feel anything else," Van Niekerk said this week at the announcement of a three-year extension to his contract with sponsor T-Systems.
"But the reality is I still need to respect where the body's at and what the body's capable of doing.
"But the mentality is to go out for gold. It's what I've done for the past three years now prior to the injury and it's where my heart is still at and my mind is still at.
"That's what I believe I can do and what I did do the years before that. Obviously reality and what you want is not always the same, but I'm hoping for the same."
He frequently spoke about the need to be patient; the knee he injured playing a game of tag rugby in 2017 was still not pain-free following surgery nearly 17 months ago.
But how patient? One sensed a level of irritation when the athlete was told that former 400m hurdles great Edwin Moses had predicted it would take him two years to get back to his best.
"If I can't put a time to it then I don't know how he got that right, but I mean I've never met him before. I never had a conversation with him before.
"To me that's opinion and I respect his opinion. I've had thousands of opinions during my career, but I've also proved many of them wrong so I'm out here to work hard ... if it takes a year, so be it, if takes a few months, then so be it, if it takes two years then I guess he was spot on."
At least Moses thinks he'll get back to his best. There are sports doctors who have whispered their doubts from a distance.
Ray Wicksell, a member of the rebel American athletics team that came to SA in the late 1980s, said he suffered a similar injury and was unable to match his best times.
"I ran 3min 54sec in the mile before I was hit by a truck on a training run, and afterwards I couldn't break 3:57.
"In the 400m I was 47.4 out the blocks, couldn't break 49 after that," added Wicksell, who ran 24 sub-four-minute miles in his career, 16 of them after the accident. "I hope he [Van Niekerk] can come back, but it's going to be a hard road because it's not only a physical injury, it's a mental injury."
Van Niekerk has travelled the injury road before.
He kept breaking down as a 100m and 200m sprinter, and it was only after coach Ans Botha switched him to the 400m that he was able to stay injury free.
Van Niekerk added the 200m and 100m races to his international roster in 2017, and even last year he was hopeful of returning to all three.
Now he's singing a new tune. "You're going to miss me in that area [100m and 200m] ... I think I want to seal the 42 [sub-43-second 400m], that's where my mind and my heart is at. I want to focus and invest proper in getting that 42."
And then his passion for the short sprints quickly bubbled up again. "And then I can get back to what I really want to do - the 1 and 2," Van Niekerk added with a laugh.
His dreams, self-belief and love for the sport are still there. And the knee?
That's the million-dollar question...