Tim Tszyu is treating his US scare as a valuable learning experience in his relentless pursuit of world title glory.
Tszyu enhanced his undefeated record to 21-0 and retained the No.1 WBO super-welterweight ranking with a unanimous points decision over Terrell Gausha in Minneapolis.
But the ailing Australian - suffering from the flu - had to recover from a first-round knockdown to keep his world title dream alive in a brave performance that critics claimed raised "question marks".
Even Tszyu conceded dark thoughts crept into his head after Gausha sent him crashing to the canvas in the opening two minutes.
"Oh man, there's definitely some shit thoughts going through your head," he told Fox Sports' Main Event after being floored by a stunning right-hand blow to his head.
"That's a great lesson for myself; I got back up and I dug deep."
Asked what he still had to learn before hopefully facing the winner of the May 14 rematch between Jermell Charlo and Brian Castano in a unified mega-fight, Tszyu said: "Everything".
"Everything and anything. There's a lot more to learn. This sport, there's so much to learn.
"You've got to keep going, keep training hard and keep on improving and keep fighting warriors like Terrell Gausha."
Commentating from ringside, Australian boxing legend Jeff Fenech, agreed that Tszyu will need to address some weaknesses to be ready for Charlo or Castano after Gausha exposed the 27-year-old's defences with a series of big right hands.
"The performance was great," Fenech said.
"But there were so many different things that I've seen today that he can fix.
"He wasn't slipping to the side, making the jab miss and coming over with the right hand. He was trying to go straight through it.
"He was leading with the left hook, which left him open for the straight right hand.
"And the biggest thing was those pity-pat punches, where he was trying to set one big one up. instead of just getting to the side and working the body and then coming up."
Explaining his sluggishness, Tszyu said he'd been sick since arriving in the US almost a month ago, but didn't want to let on.
"Two days before the fight, I was coughing like a dog. Weight was a problem as well," he said.
"It was horrible. I couldn't breathe. Even now, it's still in my lungs.
"Yeah, for the first two weeks I was here in America, I was trying to drink water, trying not to show it.
"I didn't want no media finding out and having excuses and shit like that."
But he vowed to be ready for Charlo or Castano.
"I'll be in LA watching the fight ringside so whoever, man, I couldn't care less," Tszyu said.
"I'm coming for the two boys. Whoever wants it, come get it."
