Tempers flared Thursday night during a live debate between those backing the embattled 2024 Boston Olympics bid and the leaders of a grassroots group opposing the lavish sporting event.

But arguments about hosting the Olympics in Boston weren't just happening onstage.

The blows quickly spilled over to social media, where a top spokesman for the United States Olympics Committee found himself fending off insults — and lobbing back snark — from people at odds with the Olympics proposal.

Olympics detractors defended their camp online after Patrick Sandusky, chief communications and public affairs officer for the USOC, accused No Boston Olympics co-chairman Chris Dempsey several times of presenting inaccurate information.


"So how is Dempsey an Olympic Games expert again? What's his background? He hasn't presented a fact yet. Not one. Just blurting out myths," Sandusky said.

Dempsey and economist Andrew Zimbalist were pitted against Boston 2024's Steve Pagliuca and USOC official Daniel Doctoroff during the televised showdown. The event was moderated by Fox 25's Maria Stephanos and the Globe's Sacha Pfeiffer.

Residents didn't take Sandusky's remarks lightly:

But as he continued to denounce Dempsey’s claims, Sandusky’s accusatory tweets were met by a series of comments that were more personal.

As Sandusky criticized Dempsey as a liar, the USOC official was called a "hack" and an "idiot."

"More classy comments from No Boston folks," Sandusky said toward the end of the debate, when he was told to delete his account. "Noted. Stay classy."

Sandusky was also challenged about claims of his own.

During the debate, Dempsey said that Princess Norberta "Nora" of Liechtenstein is a member of the International Olympics Committee, and would have exclusive access to highway lanes reserved for Olympics VIPs if the city were to host the games.

Sandusky quickly rebuffed the notion, and said the princess wasn't an IOC member — but people arguing with Sandusky were quick to prove him wrong.


"It's unfortunate that Sandusky would call me a liar for saying the Princess of Liechtenstein is an IOC board member," Dempsey said in an email. "According to the IOC website, Princess Nora has been a member since 1984. Anyone who can use Google could look that up — but I guess he didn't. It's ironic that he called me the one without expertise."

These types of pitched exchanges represent a subset of emerging social media debates pushed by residents opposed to hosting the games.

But Pagliuca has said organizers have thick skin.

"A lot of them are very thoughtful. There are some that are not as thoughtful. But we're taking it all in," he told the Globe last month.

Steve Annear can be reached at steve.annear@globe.com. Follow him on Twitter @steveannear.