Mark Cuban is locked in a Twitter war with Donald Trump's biggest online broadcaster and a poker legend

Billionaire businessman Mark Cuban, the Right Side Broadcasting Network, and poker legend Mike Matusow engaged in a lengthy Twitter war Tuesday over the size of the crowd at Donald Trump's Cincinnati rally last week.

It began when Cuban, the owner of the NBA's Dallas Mavericks, star of ABC's "Shark Tank," and a prominent supporter of Democratic nominee Hillary Clinton, tweeted an Instagram photo from the Trump rally. It showed the upper deck of the arena virtually empty.

"So @USBankArena holds 17k and it's half empty or worse," Cuban wrote. "Your crowds are shrinking Donald #trumpmath."

That's when Matusow, a Trump supporter, chimed in. He asked Cuban not to be "fake" like the media.

"Well at least u showed Msm view instead of other view @RSBNetwork shows where its totally packed don't be like fake msm no facts!!" he posted.

Cuban fired back, saying Matusow has a "polluted" mind.

"lol," he posted. "I pulled them from some attendees' Instagram. Your mind is so polluted u couldn't read the Instagram url."

Matusow then shared a video clip from Right Side Broadcasting, a pro-Trump network that broadcasts all of the Manhattan billionaire's rallies online.

"Here's a real view for you!!" Matusow wrote.

The video showed the packed lower bowl but did not give a view of the upper-deck Cuban had referenced. Trump himself frequently touts the size of his crowds at the rallies and criticizes media outlets for not panning their cameras to "show the crowd."

"Lots of empty seats and just lower bowl," Cuban responded. "You do realize the video and pic I posted were taken the same time?"

Right Side Broadcasting's account then began engaging, asking Cuban to "find one video" where Clinton "has got 1/5 of this crowd at ANY rally."

"Hell, I'll settle for 1/10," the account posted.

Cuban asked the network how it could "explain all the empty seats?"

The network replied that Trump was "kickin' her tail" in Ohio.

The battle cooled off shortly after.

"The place was not full, but there was a lot of ppl," Right Side Broadcasting wrote. "Let's all slow our roll and settle this in 3 weeks, baby."