John Kasich won his first primary election Tuesday in Ohio, claiming all 66 delegates in the winner-take-all state, CNN and Fox News projected.

Despite being a popular governor in Ohio, having easily won a second term to the governorship (he won all but two counties in Ohio's 2014 gubernatorial election), Kasich wasn't necessarily guaranteed a win.

Ohio was nearly split between Kasich and GOP frontrunner Donald Trump in the days leading up to the primary.

Trump was polling within 5 points of Kasich and tied in some metrics, leaving the possibility for Trump to pull off a narrow win.

But Kasich's success in Ohio, his only win in the primaries so far, has important implications: It stopped Trump from getting another 66 delegates and pushed forward the Republican establishment's plan to stop Trump's overarching lead by preventing him from gaining a majority of the delegates for the Republican convention.

This was an important win for Kasich, but not for the reason you might think

With Ohio under his belt, Kasich has only won one state and placed second in New Hampshire.

Based on the delegate math and his polling numbers in the remaining primaries, Kasich's only real hope to win the nomination is preventing Trump from winning a majority of delegates and forcing a brokered convention, where the delegates can decide the nominee.

Kasich's rival Marco Rubio, who has become increasingly aware of this reality for his campaign as well, told his supporters to vote for Kasich in Ohio for this exact reason.

"John Kasich is the only one who can beat Donald Trump in Ohio," Rubio said at a press conference on the campaign trail. "If a voter in Ohio is motivated by stopping Donald Trump, I suspect that’s the only choice they can make."

Rubio said there was no quid pro quo with Kasich, which Kasich basically confirmed by telling his supporters to vote for him rather than Rubio in Florida. In the world of strategic voting, Kasich's win in Ohio was an important step in the plan to dethrone Trump.