Tim Tszyu is treating his US scare as a valuable learning experience in his relentless pursuit of the world title.
Tszyu extended 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 - stricken with the flu - had to overcome a first-round knock to keep his world title dream alive in a valiant performance that critics claimed raised "question marks".
Even Tzu admitted that deep thoughts ran through his head after Gausha crashed onto the canvas in the opening two minutes.
"Oh man, you definitely have some bullshit thoughts going through your head," he told the Fox Sports main event after a surprise right-handed blow to his head.
"It's a great lesson for me; I got back up and I dug deep."
When asked what he still has to learn before facing the winner of the May 14 rematch between Jermel Charlo and Brian Castano in a unified mega-fight, Tszyu said: "Everything".
"Everything and anything. There's so much more to learn. This game, there's so much to learn."
"You have to keep going, keep working hard and keep improving, and keep fighting warriors like Terrell Gausha."
Commenting from ringside, Australian boxing legend Jeff Fenech agreed that after exposing Gausha's 27-year-old defense with a series of big right-handers, Tzu had some weaknesses to prepare for either Charlo or Castano. will need to be removed.
"The performance was great," Fenech said.
"But there were so many different things that I saw today that he could fix.
"He wasn't going to the side, was missing the jab and was coming off the right hand. He was trying to go straight through it.
"He was leading with the left hook, which left him wide open for a straight right hand.
"And the biggest thing was those pity-pit punches, where he was trying to set up a big one. Instead of just going to one side and working the body and then coming up."
Describing his lethargy, Tszyu said that he had been ill since coming to America about a month ago, but did not want to let go.
"Two days before the fight, I was coughing like a dog. Weight was also a problem," 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 any media to find out such excuses and nonsense."
But he vowed to be ready for either Charlo or Castano.
Tszyu said, "I've been watching the fight in the ring in LA, so whoever, man, I couldn't care less."
"I'm coming for two boys. Whoever wants it, bring it."