AUSTIN — Ted Cruz has one message for fellow conservatives: Take the November elections very seriously or risk losing races to Democrats.

"This is not an ordinary cycle," he told the crowd at the Resurgent Gathering, a conservative conference in Austin this weekend. "The far left is filled with anger and rage, and we underestimate that anger at our peril."

Highlighting his own race against Democratic congressman Beto O'Rourke of El Paso, Cruz told the audience that his campaign was being out-raised and that voter complacency among Republicans was his biggest challenge.

"We do have a real race and we are taking it deadly serious," Cruz said.

The senatorial race in Texas has been deemed the marquee match-up by political observers in the state.

Cruz painted O'Rourke as a "far left" candidate, who was further to the left than Senators Bernie Sanders and Elizabeth Warren. Despite that, Cruz said, O'Rourke was still the top Democratic fundraiser in the country because liberal voters were motivated to win elections in November.

Unlike Gov. Greg Abbott who said on Friday that "Texas would stay red," Cruz expressed concern that Democrats could make inroads up and down the ballot.

US Senator Ted Cruz is pictured on stage at Ferris Wheelers Restaurant in Dallas on July 28. (Louis DeLuca / Staff Photographer)

"This whole state can flip blue like that," he said. "The energy and fury on the other side is dangerous, and we need to treat it deadly serious."

Cruz called on conservative activists at the gathering to mobilize voters.

"The danger is they stay home, they're demoralized, they're less energized," he said. "What anyone can do is speak, give and vote. Mobilize voters to come out."

During Cruz's conversation with conservative blogger Erick Erickson, a protester holding a sign that read "Cruz: Russian Bootlicker," yelled: "You're a coward, Ted. Fight the trade war. Stand up to Russia. Stand up for all of Texas."

The protester yelled "Beto! Beto! Beto!" as he was escorted out of the conference.

Cruz brushed off the incident as an example of how opponents on the left were "foaming on the mouth unhinged."

He said the atmosphere in Washington remained "utterly insane" but praised the administration's actions on tax cuts, cutting regulations, undoing Obamacare and appointing conservative judges to federal courts.

"The substance of what we're getting done I think has been very remarkable," he said. "I think we need to keep at it and keep working to deliver on the promises."

But Cruz was also critical. He said federal spending that added to the national deficit remained a problem and that Trump's handling of a press conference with Russian President Vladimir Putin was "a mistake."

He also said Trump said a lot of things on Twitter "that I wouldn't say" but the outcomes had been largely positive for the country, with low unemployment rates, especially among African-Americans and Hispanics.

He criticized the president's political opponents for their vocal opposition and said Trump's supporters should respond by being "happy warriors."