While political pundits gave former First Lady Hillary Clinton the victory in the first Democratic presidential debate, her main challenger, Bernie Sanders, was the clear winner on social media.

The Vermont senator was the most mentioned candidate on Facebook and Twitter, according to social media analysis platforms Wayin and Brandwatch. He also was the most searched candidate on Google by more than a 2-to-1 margin.

Sanders was the candidate of the moment on Facebook and Twitter when the debate focused on the controversy over Clinton's decision to store emails on personal computers.

© Ted Soqui/Ted Soqui Photography/Corbis

"The American people are sick and tired of hearing about your damn emails," Sanders said in what appeared to some as a show of support for Clinton. She's been roundly criticized for also relying on a private email address as well as her government email account while serving as secretary of state.

Although trailing by almost a 2-to-1 margin in some polls, Sanders was the frontrunner on social media even before Tuesday's debate in Las Vegas and remained in the lead throughout the two-hour-long debate.

"It is rare indeed to have one candidate boast the greatest volume of mentions, the most positive sentiment within categorized mentions and several moments where mentions peak," said Kellan Terry, a data analyst with Brandwatch. "Sanders simply dominated the debate, socially speaking."

Mentions on Facebook and Twitter are valuable for the candidates, who are increasingly turning to social media to court voters as the platform plays an increasingly bigger role in how Americans consume political news and information. A survey conducted by the Pew Research Center before the 2014 mid-term elections found that 16 percent of registered voters followed candidates or other political figures on social media, a sharp rise from 6 percent during the 2010 mid-term elections.

Sanders was mentioned more than 407,000 times online during Tuesday's debate, more than double than Clinton (131,000 mentions) and fellow candidates former Virginia Sen. Jim Webb (163,000 mentions), former Rhode Island Gov. Lincoln Chafee (72,000 mentions) and former Maryland Gov. Martin O'Malley (28,000 mentions), according to Brandwatch.

There were more than 3.5 million tweets during a 24-hour period before and after the debate, Wayin reported. While Clinton and Sanders were virtually tied in terms of positive tweets, Sanders had the most popular hashtags including #DebatewithBernie, #BernieWatch and #FeeltheBern.

Wayin

"We could start to see the shifting of what's happening on social play out in the polling," said Jordan Slabaugh, Wayins' vice president of marketing.

It's also important to note that Sanders' campaign paid for Twitter's promoted hashtag of the day, #DebatewithBernie, to help expand his online reach beyond his followers, Brandwatch's Terry said. Twitter recently teamed with mobile-payments company Square to let users contribute to political campaigns.

"So perhaps [Sanders] was attempting to create a larger social conversation all along," Terry said.

Sanders also gained more new fans than his political rivals on social media as a result of the debate. He attracted more than 24,000 followers on Facebook, compared with more than 7,700 for Clinton, according to Engagement Labs, a social media measuring tool. Sanders added nearly 48,000 new followers on Twitter, compared with more than 25,000 for Clinton, Engagement Labs CEO Bryan Segal said.

"Sanders is resonating really well because he's humanizing himself and that's playing up perfectly into the social media sphere," he said.

But that may not translate into enough votes for Sanders to win the Democratic nomination, said Corey Cook, dean of the School of Public Service at Boise State University. "He certainly has the energetic part of the Democratic base, but Hillary Clinton is still light years ahead of the field."

On Facebook, which co-sponsored Tuesday's debate with CNN, 4.2 million people created more than 10 million debate-related items, including Likes, posts, comments and shares, the social network said.

"We believe this is the election where Facebook is replacing that traditional town hall format and enabling civic engagement and discourse that's across the spectrum of opinion," said Facebook's data editor Robert D'Onofrio.