Story highlights "John McCain has fallen down on the job. He's gotten weak. He's gotten old," Kelli Ward said

McCain is the eighth-oldest senator currently serving

Washington (CNN) Sen. John McCain's primary opponent is standing by her criticism one day after she declared that the soon-to-be 80-year-old Arizona Republican is too old to be re-elected.

"John McCain has stayed in Washington, D.C. for way too long -- almost four decades," she told CNN's Brooke Baldwin Friday, saying that McCain and his own family members had reservations about his age. "The Arizona voters will decide if they want an 80-year-old senator or not."

McCain is the eighth-oldest senator currently serving. The oldest is California Democrat Dianne Feinstein, 83, who has two more years left on her term.

The Arizona GOP primary election is set for Tuesday and McCain is the favorite to win yet again.

CNN/ORC poll of Arizona released Wednesday showed McCain leading Ward 55% to 29% among likely Republican primary voters. The poll also found McCain ahead of his likely general election opponent, Ann Kirkpatrick, by 52% to 39% among registered voters.

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