BERNE (Reuters) - Vladimir Klitschko retained his world heavyweight titles with a sixth-round win over challenger Tony Thompson on Saturday.
Klitschko, 36, floored the American challenger and, although Thompson got up, the referee ended the contest.
Thompson, who also lost to the Ukrainian in 2008, had been knocked down in the previous round but survived the count.
Klitschko holds the WBA, IBF, WBO and IBO titles while his older brother Vitali has the WBC crown.
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