Chagaev, 29, nicknamed the "White Tyson", won by all three judges of 117-110, 117-111 and 117-111.
Skelton, a 40-year-old who took up professional boxing only in 2002, put up a decent fight but lacked the defensive skills to ward off southpaw Chagaev’s powerful punches.
Chagaev, a two-time amateur champion, was about 11 kg lighter than Skelton, but already had proved he could beat bigger men. He won the WBA title last April by beating 2.13-meter Russian Nikolai Valuev, the biggest and heaviest champion in boxing history.
He had been scheduled to face Sultan Ibragimov, the World Boxing Organisation (WBO) champion, in a title unification bout last October but pulled out because of illness.
