Sen. Marco RubioMarco RubioRubio apologized to Trump for 'small hands' crack Sunday shows preview: Bernie soldiers on Fla. Senate candidate bashes Rubio MORE (R-Fla.) has cut Donald TrumpDonald TrumpTrump slams 'totally biased' judge in Trump U case Ex-pharma CEO Martin Shkreli: I didn’t endorse Trump Five things Clinton needs to do to win the California primary MORE's lead in Florida to single digits, according to a Monmouth University Poll released Monday.
Trump leads Rubio by 8 points in the senator's home state, 38 percent to 30 percent.
It's a significant shift from earlier polls that found Trump with a double-digit lead.
Florida is a must-win state for Rubio, who would not have much of a path to the GOP nomination without a victory in his home state.
The loss would also be a significant blow to Trump, given that Florida is a winner-take-all state awarding 99 delegates.
The Monmouth poll finds Sen. Ted CruzTed CruzStephen Hawking: Trump a 'demagogue' Dems to Clinton: Ignore Trump on past scandals Meet the billionaire donor behind Hulk Hogan’s lawsuit against Gawker MORE (R-Texas) taking 17 percent and Ohio Gov. John Kasich winning 10 percent.
Rubio leads the front-runner among the about 1 in 5 voters who have already cast their ballots, 48 percent to 23 percent. Trump leads among those who haven't voted yet, 42 percent to 26 percent.
In a hypothetical head-to-head vote between Trump and Rubio in the state, Trump still edges Rubio out, taking 47 percent of the vote to Rubio's 45 percent, according to the poll.
The poll was conducted by phone from March 3 to 6 among 403 Florida voters likely to vote in the Republican presidential primary. There is a margin of error of 4.9 percent.
Florida, which has 99 delegates at stake, will hold its primary on March 15.
The RealClearPolitics average of polls also shows Trump leading Rubio in Florida, but by a larger margin. Trump holds an 18.7 percent lead over the senator.
On Saturday, Rubio declined to say whether he will drop out of the race if he loses his home state primary.