Donald Trump may be on his way to stripping an important Ohio win from Gov. John Kasich in his home state, a new poll has found.

The New York real estate mogul is leading Kasich 31% to 26% among likely Republican primary voters in Ohio, according to a Quinnipiac University poll released Tuesday. Nearly 80% of Trump’s supporters say their mind is made up, which is the highest percentage among supporters for other GOP candidates, the survey says.

Trump won South Carolina’s Republican primary on Saturday, but his current five-point lead in Ohio could change and “anything can happen” in the three weeks leading up to the state’s Republican primary, said Peter Brown, the assistant director of the Quinnipiac poll. Kasich has the best favorability rating at 77%, according to the poll.

“A Kasich Ohio win is crucial to the Republicans trying to stop the New York businessman’s nomination,” Brown said in a statement. “If Trump can defeat Kasich in his home state, that would be an impressive demonstration of his strength in a state that is just now getting attention.”

Poll results also show that Hillary Clinton is leading Bernie Sanders, polling at 55% among Ohio likely Democratic primary voters compared to Sanders’ 40%.

Quinnipiac University surveyed 759 likely Ohio Republican primary voters and 518 Ohio likely Democratic primary voters from Feb. 16 to Feb. 20. The margin of error was plus or minus 3.6 percentage points for Republicans and 4.3 percentage points for Democrats.

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