Republican presidential candidate John Kasich is projected to win the Ohio primary, knocking off rival Donald TrumpDonald TrumpJeb Bush: Reports of father supporting Clinton were 'inappropriate' Trump: I have 'very good' marital history Report: Trump Foundation lacks proper certification MORE to secure a critical victory that increases the likelihood of a contested convention.
Kasich's win gives him all 66 of the state's GOP delegates.
Fox News and CNN called the race at about 8:45 p.m. EDT, just over an hour after polls closed.
Kasich got a late assist on the trail from 2012 GOP presidential nominee Mitt Romney, who campaigned at his side.
And rival Marco RubioMarco RubioOvernight Finance: Lawmakers float criminal charges for Wells Fargo chief | Scrutiny on Trump's Cuba dealings | Ryan warns of recession if no tax reform The Trail 2016: Just a little kick Opposition to Obama's radical disarmament agenda has proven effective MORE, who had practically no chance iof taking n Ohio, had told supporters in the state to vote for Kasich to try to keep the state's delegates out of Trump's hands.
Trump's loss makes it tougher for the businessman to clinch the nomination outright before the GOP convention. He gains no delegates from Ohio because of the winner-take-all rules.