Sen. John McCain defeated former state Sen. Kelli Ward in Arizona's Republican Senate primary, setting up a general election matchup against Democratic Rep. Ann Kirkpatrick, who ran uncontested in the party's primary Tuesday.
With little more than the early vote from Maricopa County counted, the longtime incumbent led Ward 55 percent to 35 percent, according to the Associated Press.
The five-term senator was expected to defeat the conservative hardliner Ward, who raised comparatively little money while struggling to gain traction with Republican voters. Big-money Republican groups that have previously regarded McCain with skepticism, like the free-market group Club for Growth, never endorsed Ward.
The race wasn't without fireworks at the end, however. Ward repeatedly accused McCain of being too old to serve in the Senate, a suggestion that drew criticism itself and did little, apparently, to sway voters. McCain turned 80 on Monday.
The GOP standard-bearer Donald Trump publicly withheld his endorsement of McCain earlier this month. But Trump backtracked days later.
Democrats consider Arizona a second-tier pickup opportunity in a state where Hillary Clinton is running close to Trump in the presidential race. Kirkpatrick, though, has a history of winning battleground House races.
McCain's only other major primary challenge came in 2010 from former Republican Rep. J.D. Hayworth, who ended up losing by more than 20 points.