Washington (CNN) North Carolina's Rep. Robert Pittenger became the first House incumbent to lose his seat in a primary in the 2018 midterm election cycle, conceding the race Tuesday to conservative pastor Mark Harris.

Pittenger, a 69-year-old Republican who was first elected in 2012, trailed Harris by 2 percentage points with just one precinct left to report.

It was a rematch of their razor-tight 2016 primary, with government spending taking center stage. Harris hammered Pittenger's vote for the omnibus spending bill, while Pittenger shot back that Harris couldn't claim to be supportive of President Donald Trump while opposing the measure, which included Trump's increases in military funding.

The 6th District seat, which stretches southeast of Charlotte, is a battleground in November, and in a sign of Democratic enthusiasm, the party's leading candidate, 34-year-old Marine veteran Dan McCready, got more than 4,000 more votes in his primary than Pittenger and Harris combined.

Pittenger was the fourth House Republican to lose on Tuesday, though the other three were seeking Senate seats. Reps. Todd Rokita and Luke Messer lost the Senate primary in Indiana, while Rep. Evan Jenkins finished second in the Senate primary in West Virginia.