Roger Marshall has won the Republican Senate nomination in the state of Kansas, media reported on late Tuesday.
He is going to compete with Democratic state Senator Barbara Bollier, who won her party's nomination.
In a phone call on Tuesday, President Donald Trump congratulated Marshall and other Republicans on the victory, saying, "that's a big night".
Another Republican senator, Martha McSally, won the Senate nomination in Arizona on Tuesday, the New York Times reported, defeating businessman Daniel McCarthy. She is going to face off against Democrat Mark Kelly in November.