Wladimir Klitschko denied playing mind games with Anthony Joshua as the pair came face to face in New York.
Klitschko and Joshua are set to meet at Wembley on April 29, for the IBF and vacant WBA (Super) and IBO heavyweight titles.
But the fun began at Madison Square Garden on Tuesday as Joshua accused his Ukrainian opponent of trying to get an early advantage.
"I'm feeling the jet lag a bit so excuse me if I'm lost for words," the Brit said after Klitschko had spoken for several minutes at a news conference.
A laughing Klitschko replied: "Did I put you asleep already with my last speech?"
"No, no. It's interesting because this now is all about the mind games," Joshua said.
Klitschko replied: "No, no, no. This is not mind games."
Joshua, 27, believes he is ready for the huge fight against a man 13 years older and with 50 more bouts to his name.
"I feel whatever occasion has been put in front of me in the early stages of my career, I've always overcome," he said.
"People say, 'how do you feel about fighting in front of 90,000 people? Could you ever picture it?' And I say no.
"But I don't think God would ever put me in a position that I couldn't handle. So I'm here for a reason and I'll handle business the same way I've been handling business.
"And even though I'm in front of 90,000 people and the world watches, the objective still remains the same and that's to be victorious."