"Well, I'm going to show up. He gets to decide what he's going to do, but I will be there," Clinton told reporters during a gaggle on her campaign plane.
"If I'm the only person on stage," Clinton continued, shrugging, "Well, you know, I'm the only person on stage."
Clinton put Trump on the defensive during their debate Monday night as the pair clashed in the first of three televised debates this cycle.
Clinton campaign chair John Podesta said the campaign was "very worried" that Trump's campaign may plot a way to pull out of the two remaining debates after Monday's event.
Former New York City Mayor Rudy Giuliani, a Trump adviser, floated the prospect of Trump skipping future debates and criticized NBC's Lester Holt, Monday night's moderator.
But Trump told Vice News in a brief interview after the debate Monday that he would "100 percent" participate in subsequent debates.
The next debates are set for Oct. 9 at Washington University in St. Louis, Mo., and Oct. 19 at the University of Nevada-Las Vegas.