"I think there's a question now whether he will do the other debates," John Podesta told MSNBC after the debate at Hofstra University.
But Trump and his campaign gave no indication that the Republican presidential candidate will not attend the two additional debates. The second and third debates take place on Oct. 9 and 19, respectively.
Trump never lost it but did appear flustered at points during the debate and gave rambling answers to some policy questions. He hit Clinton on some policy points like trade.
Dow futures turned positive on Monday night, trading more than 100 points higher as Clinton appeared to gain momentum over Trump amid the debate.