John Kasich - who was re-elected as Ohio's governor in 2014 with 64 percent of the vote - is trailing Republican front-runner Donald Trump by five percentage points among likely Ohio GOP primary voters, according to a poll released Tuesday morning by Quinnipiac University.
The Quinnipiac Poll had Trump with 31 percent support among Ohio Republicans, compared to 26 percent for Kasich.
With a margin of error of plus or minus 3.6 percent among the 759 GOP voters surveyed, it is by no means an insurmountable lead for Trump, with three weeks to go before Ohio's 66-delegate, winner-take-all primary.
On the Democratic side, former Secretary of State Hillary Clinton leads Vermont Sen. Bernie Sanders by 15 percentage points - 55 percent to 40 percent. The poll surveyed 518 likely Democratic primary voters, with a margin of error of plus or minus 4.3 percentage points.
Among the other GOP presidential candidates, Sen. Ted Cruz of Texas was third with 21 percent, while Sen. Marco Rubio of Florida had 13 percent and Ben Carson was at five percent support.
Trump is starting the final three weeks of the Ohio presidential primary campaign "on the right track,'' said Peter A. Brown, assistant director of the Quinnipiac University Poll.
"A Kasich win is crucial to the Republicans trying to stop the New York businessman's nomination,'' Brown said. "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. But Trump's lead is just five points, certainly not enough for him to breathe easy."
The poll also showed that 78 percent of Trump's supporters say their minds are made up, which is higher than any other GOP candidate. But Trump has the lowest favorable rating of the GOP candidates at 57 percent.
Trump's support is high among those Republicans who say they identify with the tea party movement. It is at 35 percent, compared to only 11 percent for Kasich. Tea party activists in Ohio have been critical of Kasich for his support for Common Core educational standards, his acceptance of Medicaid funds under Obamacare and other issues.