Donald Trump just got his ass handed to him by Mark Cuban.On Sunday morning, Trump attacked Cuban for no reason, claiming that the real self-made billionaire is not smart to enough to be president and that Cuban backed him  big-time. I know Mark Cuban well. He backed me big-time but I wasn t interested in taking all of his calls.He s not smart enough to run for president!  Donald J. Trump (@realDonaldTrump) February 12, 2017Of course, everyone knows that Cuban supported Hillary Clinton during the campaign, and unlike Trump, Cuban is an intelligent businessman who built his empire without a multi-million dollar head start from his daddy.Twitter responded by roasting Trump but everyone was really waiting to see how Cuban responded.Well, Cuban did, indeed, respond. And Trump is going to hate it.Cuban posted a message Trump wrote to him complaining about how Cuban talked about him on CNN and the message Cuban wrote in return.Trump called Cuban  nasty  and Cuban told Trump that he had hoped he would  dig into the issues  and do more than just run his mouth about what other people tell him. When you say there is a bubble, it sounds like you are winging it,  Cuban wrote.  Which also makes it sounds like your comments are based on who you talked to last. Which tells me you are getting bad advice. I get the big part of your base doesn t care about issue details, but to be President, to be this close, you have to know your shit. Cuban also suggested that he might run against Trump in 2020. I may go after that job someday and it could be against you,  Cuban warned.How soon they forget  . pic.twitter.com/VXcfnjj4qX  Mark Cuban (@mcuban) February 12, 2017Cuban then followed up that tweet by letting everyone know that they can chill out since it s better for Trump to tweet than it is for him to try governing since when he does he fails miserably.I don t know. But isn t it better for all of us that he is tweeting rather than trying to govern ? https://t.co/953MuEdfeu  Mark Cuban (@mcuban) February 12, 2017That is a truly sick burn. Trump is going to flip out.Featured image via Getty Images