Businessman, reality TV star and Dallas Mavericks owner Mark Cuban gave Donald Trump a taste of the Pittsburgh spirit today at a rally for Hillary Clinton.

Cuban said there's a word in this part of the country for people, the 'screamers' who 'try to intimidate you' the Trump does: a 'jagoff.'

'Is there any bigger jagoff in the world than Donald Trump?' he asked, using a degrading term that originated in the Pittsburgh area that's the equivalent of calling someone a jerk or worse.

The billionaire also boasted that his reality TV show, Shark Tanked, 'kicked The Apprentice's a**'.'

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Businessman, reality TV star and Dallas Mavericks owner Mark Cuban gave Donald Trump a taste of the Pittsburgh spirit today at a rally for Hillary Clinton

DON'T WORRY, HILLARY, I GOT THIS: Cuban stunningly went after Trump today a Clinton rally in his hometown of Pittsburgh

TEAMWORK: (L-R) Anne Holton, Tim Kaine (D-VA), democratic presidential nominee former Secretary of State Hillary Clinton, Mark Cuban, U.S. Rep. Mike Doyle and forme president Bill Clinton clasp hands in a chain of V-for victory stances during the campaign rally at Pittsburgh's Convention Center

Trump was the host of NBC's The Apprentice and its spin-off Celebrity Apprentice for more than a decade until he decided to run for president last year.

The final season the show with Trump as the boss performed slightly under Shark Tank, which had an average of 7.05 million viewers an episode, to The Apprentice's 6.3, per a figure in the Hollywood Reporter.

In its heydey, the show was averaging 20.7 million viewers, however.

Cuban noted today that he's a self-made man, unlike Trump, who began his business with a seven-figure loan from his father.

Entrepreneurs come up with an idea, workshop it among their friends, look to see if it's already been done, 'and then you decide whether or not to go forward.'

'What you don't do,' Cuban said, 'you don't ask daddy for a small loan of a million dollars.'

He added, 'What you know is that the best equity is sweat equity.' And the one thing that any entrepreneur or manager can control is their effort.

Cuban said he's learned over his business career that when you take a risk like that, 'maybe you make it, maybe you fail.'

'I can't count the number of times I've been fired. I can't count the number of times I've failed,' he said. 'It's a big ole' list.'

But Cuban said he knew it didn't matter how many times he failed. All he had to do was be right once.

'I want each and every one of you to know...that in Hillary Clinton's America, the American Dream is alive and well,' he said.

No city knows that better than his hometown of Pittsburgh, he said, as he talked up several local businesses.

Cuban backed Clinton on Friday via a tweet. But an endorsement had been in the works for some time, a campaign official said today.

The billionaire investor said Cuban had been to Brooklyn and meet with campaign chairman John Podesta. He 'called him on Thursday and said "I'm ready to go," the Clinton aide told reporters.

'We didn't know necessarily that he would be able to come to Pittsburgh, but it ended up working out, and we're very grateful,' the aide said of Cuban's surprise appearance at the rally.

Cuban had harsh words to say about Trump today, but a year ago, when Trump got into the race, he praised the Republican on his Cyber Dust app. 'I have to honestly say he is probably the best thing to happen to politics in a long time,' Cuban said.

As late as last month he told Fox Business he was thinking about casting his vote for the fellow billionaire.

If Clinton were to add Massachusetts Senator Elizabeth Warren to her ticket, he said, 'there’s a good chance I'll vote for Donald Trump.'

STARSTRUCK: Mark Cuban shakes hands with Bill Clinton during the rally in the billionaire's hometown on Saturday night

Cuban had harsh words to say about Trump today, but as recently as a month ago he said he'd consider voting for him

The basketball team owner said in May he'd be open to serving as VP for either Trump or Clinton.

Trump's camp immediately shot down the idea. Clinton said she'd consider it. Trump tapped Indiana Governor Mike Pence in mid-July, and she went with Virginia Senator Tim Kaine, instead.

Cuban seemed to do a 180 on Friday when he said of Trump on Twitter, 'This guy should be commander in chief?'

He apparently had a change of heart over the last month as he was in talks with the Clinton campaign.

The independent had also said last year on his message-sharing platform he wants to be a Republican but the GOP 'does everything possible to discourage leadership.'

'They want dogma. They want conformity. They want to conserve their romanticized past. That's a shame. I wish they wanted to conserve the best of what America is today and find a leader that can take us to new places that make our future better.'

His position on leadership clearly factored into his decision, as Cuban spent a portion of his speech today defining it. Leadership is about 'creating consensus,' he said.

'Leadership is getting on a bus and going city to city to talk to and connect to people and listen to whats important to them. You think Donald Trump's gonna get on a bus?' he asked.