John Ruiz has warned David Haye not to underestimate him ahead of their WBA heavyweight title bout at the MEN Arena on April 3.
Haye is gearing up for his first defence of the belt he won when he claimed the scalp of Russian giant Nikolai Valuev in November last year but it is a showdown with the Klitschko brothers - Wladimir and Vitali - that he really wants as he aims for world domination.
The bookmakers make the South Londoner a massive favourite to retain his crown but his opponent, dubbed The Quiet Man, believes he is setting himself up for a fall if he contemplates a fight against the all-conquering Ukrainian-born siblings.
Speaking to Sky Sports News, Ruiz said: "I'm there for the long haul. For David Haye to think about anybody else is going to be a big problem.
"I don't want to hear the excuses afterwards - I was thinking about this guy when I should have been thinking about this guy."