Former car dealer Bernie Moreno, endorsed by Trump, wins Ohio Republican Senate primary.

Moreno to challenge Democratic incumbent Sen. Sherrod Brown in a high-stakes race.

Brown highlights bipartisan work and executive relationships; Moreno campaigns as an outsider with a populist approach.

The campaign sees mutual attacks: Brown painted as closely aligned with Biden, Moreno as an unprincipled businessman.

The outcome of this closely watched race could impact the balance of power in the Senate.