OKLAHOMA CITY - It’s official: a runoff will decide who will be the GOP candidate for governor.

Former Oklahoma City mayor Mick Cornett will advance to the runoff and will face Tulsa businessman Kevin Stitt on Aug. 28.

In a field of 10 Republican candidates, 59-year-old Cornett won the most votes of the votes.

“We really got outspent and still won,” Cornett told a cheering crowd of supporters Tuesday night after he advanced to the runoff. "One step closer to being the governor."

Cornett is a former television reporter who was first elected mayor of Oklahoma City in 2004 and served four consecutive terms during a revitalization of the state's capital city.

By 10 p.m. and with multiple precincts still not accounted for, it was too close to call between Lt. Gov. Todd Lamb and Stitt.

Shortly after 10 p.m., Lamb conceded the primary and Stitt became Cornett's challenger for August.

Lamb had the second highest amount of votes for most of the night, but lost his edge to Stitt as the night wore on. 

Stitt is the CEO of the Gateway Mortgage Group. He started the company in 2000. 

He said his business experience is why he’s fit to be the next governor.

“Running state government is a lot like running a business,” Stitt said. “It’s stuff I do every day in the private sector.”

The Libertarian candidates will also be in runoff. Chris Powell and Rex L. Lawhorn will face each other in the runoff on Aug. 28.

Whoever wins the Republican runoff will face Democratic candidate Drew Edmondson who served as state attorney general from 1995 to 2011 and the winner of the Libertarian runoff on Nov. 6.