Anthony Joshua Says 'Big Baby' Won't Want Rematch After I Beat His Ass!

Anthony Joshua says Jarrell "Big Baby" Miller shouldn't worry about that "bitch ass rematch clause" in their fight contract ... because after AJ beats him down, Miller won't want to do it again anyway!

The UK boxing superstar was in a GREAT mood in NYC on Wednesday -- despite getting pushed around by Miller during their press conference on Tuesday.

When asked if Miller crossed a line when he put his hands on Joshua, the heavyweight champ told Adam Glyn it's "just playground stuff" ... and Miller will get his beating on June 1.

"I don't take that stuff too seriously," Joshua said.

As for the rematch clause, Miller told TMZ Sports ... Joshua required him to put it in the contract just in case Miller knocks him out. Miller told us he's already preparing to beat Joshua twice.

But, Joshua says he ain't scared -- and it's "Big Baby" who should be worried.

"To be honest, after I finish him, I don't think he'll want a rematch anyway ... so I'm not gonna focus on that."