Key US senators John McCain and Marco Rubio won their Republican primaries Tuesday, setting up high-profile re-election efforts in November as their party fights to retain control of Congress.
Freshman lawmaker Rubio of Florida easily defeated business executive Carlos Beruff, securing around 72 percent of the vote and setting up a clash with House Democrat Patrick Murphy.
The closely watched Florida matchup is considered to be among those that could tip the Republican-controlled Senate into Democratic hands in November, especially if presidential hopeful Donald Trump underperforms in the general election and drags down other Republicans on the ballot.
About a third of the 100-member Senate and the entire House of Representatives are up for grabs in November.
Rubio, 45, was a rising Republican star whose presidential bid fizzled in March when Trump, a brash billionaire real estate mogul, thrashed him in the Florida primary.
Rubio had pledged to return to private life, but reversed course and launched his Senate re-election bid, scaring nearly every challenger out of what had been a crowded Republican field.
He called it "an unusual road back" to the Senate.
"But I just couldn't be at peace with the idea that we were going to not just potentially lose the Senate seat but lose the balance of power in the Senate at this critical moment in our nation's history," he told supporters after claiming victory.
Veteran Senator John McCain of Arizona was projected to handily win his contest against a more conservative candidate and advance to the November election.
"This one has a ways to go yet, and it's not going to get any easier," he said in a victory speech.
Although his rival Kelli Ward, a former state senator, is an avid Trump supporter, the Republican nominee eventually backed McCain's re-election bid, depriving Ward of much-needed political oxygen to mount a successful challenge.
She had argued that McCain, who turned 80 on Monday, had grown too old and "weak" to serve another six-year term.
McCain, the 2008 Republican presidential nominee, has spent three decades in the Senate. He was seen as one of the senators most vulnerable to a challenge by the far right, but ultimately prevailed easily.
Tuesday also saw House Democrat Debbie Wasserman Schultz, an embattled Florida congresswoman who until recently chaired the Democratic National Committee, survive a spirited challenge.
She stepped down from leading the DNC in July after leaked internal emails showed that members of the organization, which pledges neutrality in presidential primaries, favored Hillary Clinton this year over her more liberal rival Bernie Sanders.