Deontay Wilder believes Tyson Fury is scared and will be having sleepless nights before their world heavyweight title rematch later this month.
The pair fight in Las Vegas on 22 February for Wilder's WBC championship.
Their bout in December 2018 ended in a controversial draw with the American knocking Fury down twice, although the Englishman also thought he had won.
Speaking on a media conference call from the United States on Tuesday, he added: "Deep down I feel he's nervous, very nervous from what happened the first time.
Both men are unbeaten with their draw in Los Angeles 14 months ago being the only time they have not won a professional fight.
Fury, 31, last fought against Sweden's Otto Wallin and, despite sustaining a bad cut close to his eye early on, won via a unanimous points decision.
However, since then Fury has changed trainers, moving from Ben Davison to Javan 'Sugar' Hill Steward, the nephew of the late Emmanuel Steward, who trained Lennox Lewis and Wladimir Klitschko.
Wilder not worried about 'coward' Joshua
Wilder won the WBC heavyweight championship in January 2015 and has successfully defended the belt on 10 occasions - the same number of defences as legendary heavyweight Muhammad Ali managed between 1974 and 1978.
The other major heavyweight titles - the IBF, WBA and WBO - are held by Britain's Anthony Joshua after he regained the belts in December by winning a rematch against Mexican-American Andy Ruiz, a fighter he lost to six months earlier.
But Wilder, who has 42 wins and one draw as a professional and never fought Joshua, said: "I'm not worried about that coward, he barely got his titles back, never mind trying to step in the ring with the king.