Briton Anthony Joshua has said his first career defeat at the hands of Andy Ruiz Jr. was down to a lack of experience and he has become a “smarter” fighter ahead of December’s rematch.

Mexican-American Ruiz produced one of boxing’s biggest upsets when he dethroned the previously undefeated world heavyweight champion with a seventh-round stoppage at New York’s Madison Square Garden in June.

The WBA, IBF and WBO heavyweight title rematch – dubbed the ‘Clash on the Dunes’ – will take place in Saudi Arabia on December 7 after former Olympic champion Joshua triggered a rematch clause.