In 2014, the GOP primary between Thad Cochran and Chris McDaniel was a nasty nasty knock-down drawn out fight where Cochran won by utilizing the open primary system and cooperating with the African-American community. Had McDaniel won, it could have been a competitive general election (let's say 30% odds of winning for the Democrat at best).
Travis Childers was a term-and-a-half conservative democratic congressman with good WWC ties in the appalachian north of the state. Against McDaniel, black turnout might have been up and more moderate conservative turnout could have been down (Cochran had good AA community ties, McDaniel not so much).
What if Childers won the Senate Race?