Wladimir Klitschko has warned David Haye he will have the last laugh as he shrugged off his opponent's latest "childish" publicity stunts.
Haye has continually sought to goad his Germany-based nemesis in the build-up to Saturday's heavyweight unification bout in Hamburg with a succession of distasteful comments and publicity stunts.
He tweeted a link to a film featuring an Adolf Hitler character that has mock subtitles referring to preparations for Saturday's fight. The mind games continued at this afternoon's public work-out when the WBA champion trained in a southpaw stance rather than his usual orthodox position and hardly threw a punch before taking a bow and leaving.
Klitschko shrugged off his rival's actions.
"It's childish," said the IBF/WBO champion.
"I have to call it what it is. It's childish. I can't even take it seriously. It's not even funny any more.
"It's serious business, it hurts, it won't be funny for David Haye.
"There is an English saying: 'He who laughs last, laughs loudest'."
Haye is in danger of sacrificing public support in Britain due to his crude trash-talking and boorish actions.
However the 30-year-old, who spent much of his training camp in Miami, actually claims Americans and other fight fans around the world are eager for him to win at the Imtech Arena.
He said: "Their message is 'get Wladimir out of this division because he's killing it!'
"The heavyweight division has been dead since he's been involved in it.
"It's only now, since I've started doing my thing, that people think 'okay, let me see what this guy's all about, maybe we've got an entertaining fight here'.
"We know what Wladimir does time and time again, he jabs and grabs until the guy runs out of steam - and you're not allowed to have your asthma pump during the fight because of the chemicals in it - so they all have asthma attacks on the floor and it's over!"
But Klitschko claims even a lot of British fans are turning on Haye.
"Ask the people in England," he said.
"When I was in London I met a lot of people, at the airport and in the streets, and they were wishing me good luck.
"I said 'hold on, hold on, you're wishing me good luck? You're British, so you should be supporting your countryman, I don't understand what is going on here!'
"There are differing opinions, of course David Haye has fans and supporters but boxing fans there gave me a lot of respect.
"All the guys I've fought have had different gameplans. We saw David Haye today moving as a southpaw.
"I think he just sits in his hotel room thinking 'what else can I do, how can I p*** off Klitschko and the team and the fans?
"He's trying to create little things but little by little we're heading towards reality, which is going to be very serious."
Klitschko added: "I invited David Haye to watch my workout but unfortunately he didn't. I feel a bit bored of David Haye but I will enjoy his presence in the ring at a big stadium on Saturday."
Haye this week claimed Klitschko's trainer, Emanuel Steward, had approached him about working together in future because he supposedly expects his man to lose this weekend.
Steward rubbished the claims and Klitschko said today: "Do you believe all this nonsense? "We've been hearing a lot of trash from David Haye and this is another thing he's created in his hotel room. But little by little the reality is hitting home."