Blake Masters is the top candidate for likely voters in Arizona a day before the Republican Senate primary, according to an Emerson College poll released Sunday.

Masters leads with 40% of likely voters’ support, according to a poll sampling “very likely Republican primary voters” and people who already cast a ballot. Jim Lamon is the second most popular candidate with 22% of likely voters favoring him.

The winner of Tuesday’s primary will face a race against Democrat Sen. Mark Kelly in November. The race is considered a “toss-up” by Cook Political Report.

“For far too long Senator Mark Kelly has been complicit in allowing unchecked unfettered mass illegal immigration through our southern border. Arizonans know that Blake Masters will secure the border and enforce our laws and that’s why he will win in November.” Masters’ Campaign Adviser Katie Miller told the Daily Caller News Foundation.

Masters performs heavily among undecided voters with 42% supporting him, while 24% support Lamon, according to the poll.

The current Arizona Attorney General, Mark Brnovich, has the support of 14% of likely voters, while Michael McGuire is favored by 12% of likely voters, according to the poll.

Former President Donald Trump endorsed Masters in June for his “strong” stance on border security, support for the second amendment and pledge to cut taxes, among other conservative issues.

“Blake is Strong on Border Security, in particular, the disastrous Southern Border where people are pouring into the U.S. by the millions, and destroying our Country … Blake will turn that around quickly. Additionally, he will Cut Taxes and Regulations, be Tough on Crime, and Support our Military and our Vets. Blake will fight for our totally under-siege Second Amendment, and WIN!,” Trump said at the time.

The poll was conducted between July 28-30, according to Emerson College Polling. The margin of error was plus or minus 3.9 percentage points.

Lamon’s campaign didn’t respond to the DCNF’s request for comment.

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