Nikolai Valuev will fight John Ruiz for the vacant WBA heavyweight title in Berlin on August 30.

The WBA have set up the clash between the two top-ranked challengers after Ruslan Chagaev pulled out of his mandatory defence against the 7ft Valuev (48-1, 34 KOs) for the second time.

Valuev has fond memories of Berlin, having become the tallest and biggest boxing champion of all time there in December 2005 when he closely edged Ruiz (43-7, 29 KOs) with a 12-round majority-decision.

"Berlin is very special to me," said Valuev. "That is where I defeated Ruiz in 2005 to become world champion. Fighting in the Max-Schmeling-Halle again will be like a home match."

Valuev made four successful title defences before losing the championship to Chagaev on April 14, 2007 by a majority decision (117-111, 115-113 and 114-114).

In his previous fight in March, Ruiz won a 12-round unanimous decision over Jameel McCline in Mexico.

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