But not everyone in the New York crowd was thrilled to see the former president.
Cameras captured actress Nia Renee Hill, the wife of comedian Bill Burr, appearing to flash two middle fingers at the former president as he looks out at the audience, oblivious to the gesture.
Mr Trump entered the arena after the preliminary bouts accompanied by former Fox News host Tucker Carlson and UFC president Dana White.
His son Donald Trump Jr and Kid Rock were also among the 19,000-strong crowd.
Mr Trump, a regular UFC attendee, had earlier appeared at a rally in New Hampshire on Saturday.
The former president holds a commanding lead in the Republican presidential primary despite facing 91 indictments in four separate criminal trials and the prospect of having his business empire broken up from a civil fraud trial in New York.
His absence from the recent GOP presidential debate and continuing hold over voters was parodied in Saturday Night Live’s cold open.
A night after his own sold-out show at Madison Square Garden, Burr took his seat ringside with his wife for Saturday’s action which saw Brazilian light heavyweight contender Alex Pereira defeat Czech fighter Jiri Procházka in the co-main event.
In the other co-headliner, British heavyweight Tom Aspinall, a late replacement for the injured Jon Jones, knocked out Russian Sergei Pavlovich inside the first 70 seconds of the first round.