Republican Rep. Mike Collins on Tuesday defeated Derek Dooley and will face off against Sen. Jon Ossoff (D-Ga.) in November.Why it matters: President Trump endorsed Collins after the May 19 primary. He now faces a well-funded Democratic incumbent who's won a statewide campaign in Georgia before.Republicans view the Georgia Democrat's seat as key to maintaining control of the U.S. Senate.Zoom in: Collins won roughly 55% of the vote, according to preliminary results from Georgia Secretary of State Brad Raffensperger's office. The AP called the race for Collins just after 8:30pm with 52% of the vote counted.Dooley later conceded to Collins, the AP reported. "He ran a tough campaign, he got out early and we just never could catch him."Between the lines: The runoff became one of the clearest tests yet of the competing arguments shaping the Republican Party in Georgia and nationally: embrace MAGA or pursue an alternative path to victory. Collins, a trucking company owner who represents a red district between Atlanta and Augusta, ran as a Trump loyalist who made immigration enforcement a central focus of his campaign.Kemp, a popular swing-state governor rounding out his second and final term in office, was a Dooley campaign trail fixture.Follow the money: Collins raised $4.3 million up to the most recent disclosure deadline, according to Open Secrets. By comparison, Ossoff has raised more than $57 million and built one of the Senate's strongest campaign war chests.What they're saying: In his victory speech Tuesday night, Collins thanked Dooley for running a "spirited campaign" and Kemp for "his leadership and his friendship over the years.""We all know what the mission is here," Collins said.On X, Ossoff slammed Collins as an "extremist" and attacked his voting record on issues like the Iran conflict.What's next: The general election is Nov. 3.