Rep. John Sullivan (R-Okla.) became the latest incumbent to lose a primary on Tuesday, falling to tea party-backed Jim Bridenstine.

Sullivan survived a 2010 primary after taking time away from Congress, citing his “addiction to alcohol.” On Tuesday, he lost narrowly amidst a spirited — if under-funded — challenge from Bridenstine, a Navy pilot who raised less than $300,000 for the race.

Tea party candidate Jim Bridenstine speaks during a news conference in Tulsa, Okla. Bridenstine defeated Rep. John Sullivan (R-Okla.) in a primary Tuesday. (AP Photo/Sue Ogrocki)

Sullivan, who first won his seat in 2002, told the Associated Press recently that he didn’t take the challenge from Bridenstine seriously early enough in the campaign.

“I never had a race like this in all my life,” Sullivan told the AP. “The only mistake I made was I ignored it for too long.”

Sullivan becomes the eighth House incumbent to lose a primary. Four of those members lost to fellow members in matchups that were merged thanks to the once-in-a-decade redistricting process.

Sen. Richard Lugar (R-Ind.) also lost a primary to a challenger earlier this year.

Republicans will still be favored to hold Sullivan’s heavily conservative district.