DUESSELDORF, Germany — Eddie Chambers is promising to stun heavyweight champion Wladimir Klitschko in their title fight in March.

The American challenger, who has won 35 of his 36 fights, says he will "shock the world" when they fight at Dusseldorf's Espirit Arena. Chambers has won five straight since his only loss to promising heavyweight Alexander Povetkin.

Klitschko says his American rival should not be underestimated, even though the Ukrainian champion hasn't lost since April 2004. The fight against Chambers on March 20 will be the first for Klitschko since June.

Ticket sales began Thursday for the fight. Espirit Arena seats 51,000.