Venture capitalist Bruce Rauner won the GOP primary Tuesday in his bid for Illinois governor, as voters embraced a first campaign by the multimillionaire who flooded the airwaves with vows to run the Democratic stronghold like a business and curb the influence of government unions.

With Republicans eyeing what they view as their best shot in years to win the top job in President Barack Obama’s home state, Rauner defeated three longtime state lawmakers — including the current state treasurer. He advances to a November matchup with Democratic Gov. Pat Quinn, who easily won his nomination for a second full term.

Between Quinn and predecessor Rod Blagojevich, now imprisoned for corruption, Democrats have held the governorship since 2003. But Rauner could present a serious threat, partly due to a massive campaign bank account that already includes more than $6 million of his own money.