Donald Trump in Las Vegas. AP Photo/John Locher A new poll released on Monday illustrates a major hurdle facing Donald Trump's electoral prospects.

The Monmouth University poll found presumptive Democratic presidential nominee Hillary Clinton up seven points over Trump in a head-to-head general-election matchup. No third-party candidate received more than 10% support.

But even more alarming for the presumptive Republican presidential nominee, 49% of registered voters said that it is "very important" to make sure Trump is not elected president. The poll found that 41% said that it is "very important" to keep Clinton out of the White House.

Just 31% of respondents said that it was "not at all" important to stop Trump from becoming president, while 35% said the same about Clinton.

The gulf was even wider among self-described independent and undecided voters.

Among that group, 48% of respondents said that it is very important to prevent Trump from occupying the White House, compared to 32% who felt similarly about Clinton.

"The fear of either Clinton or Trump getting into the White House, though, may lead some to hold their noses and vote for the other major party nominee. And right now, a Trump victory appears to be the more troubling outcome for these voters," Monmouth University polling director Patrick Murray said in a statement.

Many experts caution against reading too far into statistics in national polls, though.

"Generally, it would be ideal to watch battlegrounds such as Ohio/Florida/Pennsylvania. However, state polls are sparse," Princeton University polling expert Samuel Wang told Business Insider in an email last week. "This year's states are mostly correlated with 2012, so there's no realignment. This means that watching national numbers is probably a reasonable substitute. "

Still, Monday's release is only the latest in a string of alarming statistics for the real-estate mogul.

A Bloomberg Politics poll released last week found that 55% of voters reported that they could never see themselves supporting Trump.