David Haye is confident he will fight Vitali Klitschko later this year after he has "smashed" his brother Wladimir on Saturday.

Haye has vowed to retire on his 31st birthday in October but wants to bow out as undisputed heavyweight champion by beating Wladimir this weekend and then taking on his older sibling.

Vitali, 39, is scheduled to defend his WBC belt against Tomasz Adamek in September but Haye is confident the Ukrainian will find a way to face him instead.

He said: "I'll start thinking about Vitali after the referee has counted to 10 on Saturday and I'm the new unified champ.

"We'll see. I think after the fight things will change pretty quickly, I'm positive about that."

Haye insists he will not postpone his retirement.

"There's nobody else I want to fight," he said. "Without a doubt I'm confident I'll fight Vitali in September or October.

"Once I've smashed Wladimir I'm pretty sure his big brother is going to try to step up to the plate to take revenge."

WBA champion Haye aims to add Wladimir's IBF and WBO titles to his own belt in Hamburg on Saturday. He does so as a significant underdog with bookmakers and hopes his 35-year-old nemesis is taking him lightly.

"If he's watched my last fights and is judging me on those then he is underestimating me, without a doubt," said the Englishman.

"For example during my whole campaign at cruiserweight everyone said 'if you get David past four or five rounds he runs out of steam'.

"Well, that only happened to me once, when I lost to Carl Thompson (in 2004). I wasn't going to let it happen again. The only time it happened was then and Carl Thompson took his opportunity.

"Everyone else tried that and failed. Every time they got me into the later stages they got knocked out, because I learned from the Thompson fight."

Haye is critical of Klitschko's "robotic" style but does insist the long-reigning champion is less vulnerable than his reputation suggests.

He said: "I don't believe he's chinny. He wouldn't have had the success he has had over so many years if he was chinny because he has been hit by big shots.

"How he reacts to them is different to me - does he stand and hold his ground and fight? Not that often. "But for some reason I saw in his eyes he looked like he is going to come and do something different this time round and if he does, that's fine by me."