George Groves says David Haye will not be intimidated by the Klitschkos - and suspects the wrong brother is fighting for the family honour this weekend.
Wladimir will pit his IBF, WBO and IBO versions of the world heavyweight title against Haye's WBA strap, live from Hamburg on Sky Box Office on Saturday.
But Hayemaker gym-mate Groves believes WBC king Vitali, who joined forces with little brother to goad Haye during Monday's final press conference, is showing more stomach for the battle.
"David's equal to their antics and he's not worried about them," said Groves, who feels the Ukrainian camp got the worst of the verbal sparring.
"I think they were far more rattled at the end, especially trainer Emanuel Steward, and it seemed Vitali was much more up for the fight than Wladimir.
"Wladimir, as people say, is not a natural fighter, he's the gentleman of the two. Vitali looked like he really wanted to rip someone's head off!"
The imposing presence of the Klitschkos in tandem has been enough to render most challengers impotent come fight-night but Groves is confident Haye can buck the trend.
"You look at Wladimir and he's six foot and 17 stone, and there's two of them - that's frightening in itself," he added. "But David knows he's only fighting one.
"Those little tactics won't work. David's far more comfortable being on his own. He doesn't need the help and support once he's in the ring, which I think is priceless."