World Heavyweight boxing champion Britain’s Anthony Joshua celebrates after beating challenger Bulgaria’s Kubrat Pulev in their Heavyweight title fight at Wembley Arena in London Saturday, Dec. 12, 2020. (Andrew Couldridge/Pool via AP)

World Heavyweight boxing champion Britain’s Anthony Joshua, left, throws a punch at challenger Bulgaria’s Kubrat Pulev during their Heavyweight title fight at Wembley Arena in London Saturday, Dec. 12, 2020. (Andrew Couldridge/Pool via AP)

World Heavyweight boxing champion Britain’s Anthony Joshua, center, knocks down challenger Bulgaria’s Kubrat Pulev to win their Heavyweight title fight at Wembley Arena in London Saturday, Dec. 12, 2020. (Andrew Couldridge/Pool via AP)

World Heavyweight boxing champion Britain’s Anthony Joshua, left, celebrates after beating challenger Bulgaria’s Kubrat Pulev in their Heavyweight title fight at Wembley Arena in London Saturday, Dec. 12, 2020. (Andrew Couldridge/Pool via AP)

World Heavyweight boxing champion Britain’s Anthony Joshua lands a blow on challenger Bulgaria’s Kubrat Pulev during their Heavyweight title fight at Wembley Arena in London Saturday, Dec. 12, 2020. (Andrew Couldridge/Pool via AP)

World Heavyweight boxing champion Britain’s Anthony Joshua, goes on the attack against challenger Bulgaria’s Kubrat Pulev during their Heavyweight title fight at Wembley Arena in London Saturday, Dec. 12, 2020. (Andrew Couldridge/Pool via AP)

World Heavyweight boxing champion Britain’s Anthony Joshua, right, throws a punch at challenger Bulgaria’s Kubrat Pulev during their Heavyweight title fight at Wembley Arena in London Saturday, Dec. 12, 2020. (Andrew Couldridge/Pool via AP)

World Heavyweight boxing champion Britain’s Anthony Joshua and challenger Bulgaria’s Kubrat Pulev, left, during their Heavyweight title fight at Wembley Arena in London Saturday, Dec. 12, 2020. (Andrew Couldridge/Pool via AP)

World Heavyweight boxing champion Britain’s Anthony Joshua punches challenger Bulgaria’s Kubrat Pulev during their Heavyweight title fight at Wembley Arena in London Saturday, Dec. 12, 2020. (Andrew Couldridge/Pool via AP)

World Heavyweight boxing champion Britain’s Anthony Joshua, right, hits challenger Bulgaria’s Kubrat Pulev during their Heavyweight title fight at Wembley Arena in London Saturday, Dec. 12, 2020. (Andrew Couldridge/Pool via AP)

World Heavyweight boxing champion Britain’s Anthony Joshua, right, hits challenger Bulgaria’s Kubrat Pulev during their Heavyweight title fight at Wembley Arena in London Saturday, Dec. 12, 2020. (Andrew Couldridge/Pool via AP)

World Heavyweight boxing champion Britain’s Anthony Joshua, right, and challenger Bulgaria’s Kubrat Pulev grapple during their Heavyweight title fight at Wembley Arena in London Saturday, Dec. 12, 2020. (Andrew Couldridge/Pool via AP)

World Heavyweight boxing champion Britain’s Anthony Joshua throws a punch at challenger Bulgaria’s Kubrat Pulev during their Heavyweight title fight at Wembley Arena in London Saturday, Dec. 12, 2020. (Andrew Couldridge/Pool via AP)

World Heavyweight boxing champion Britain’s Anthony Joshua lands a blow on challenger Bulgaria’s Kubrat Pulev during their Heavyweight title fight at Wembley Arena in London Saturday, Dec. 12, 2020. (Andrew Couldridge/Pool via AP)

World Heavyweight boxing champion Britain’s Anthony Joshua glares at challenger Bulgaria’s Kubrat Pulev during their Heavyweight title fight at Wembley Arena in London Saturday, Dec. 12, 2020. (Andrew Couldridge/Pool via AP)

World Heavyweight boxing champion Britain’s Anthony Joshua looks across at challenger Bulgaria’s Kubrat Pulev before their Heavyweight title bout at Wembley Arena in London Saturday, Dec. 12, 2020. (Andrew Couldridge/Pool via AP)