Rep. James Lankford (R) won the Republican primary for U.S. Senate in Oklahoma on Tuesday, defeating state House speaker T.W. Shannon (R) and five lesser-known candidates in a closely watched campaign.

Lankford, 46, took a commanding 57 percent of the vote, avoiding a runoff against Shannon that looked very possible headed into the day. Shannon had 34 percent; five others finished well off the pace.

Lankford is the fifth-ranking House Republican. He burst onto the scene in 2010 with a surprise U.S. House race win, made possible in large part by a loyal following of Christian conservative supporters from his days as the head of the largest Christian youth camp in the country.

National tea party groups and figures like Sen. Ted Cruz (R-Tex.) and the Senate Conservatives Fund rallied around Shannon, 36. The half-black, half-Native American state legislator was seen as a potential rising national star who could bring diversity to a GOP looking to shed its image as the party of mostly older, white men.

Lankford will be a heavy favorite in the general election given the state’s strong conservative ben. He is running for the seat of Sen. Tom Coburn (R), who is stepping down at the end of this Congress. ​