The latest Fox News poll shows four Republican presidential candidates beating Democratic presidential front-runner Hillary Clinton in national head-to-head matchups.

Retired neurosurgeon Ben Carson fared best against Clinton, garnering 50 percent compared to just 39 percent for the former secretary of state.

Republican front-runner Donald Trump was next, leading Clinton with 45 percent to 40 percent, while former Florida Gov Jeb Bush led Clinton 44 percent to 40 percent and former Hewlett-Packard CEO Carly Fiorina beat Clinton 42 percent to 39 percent.

On the other hand, Vice President Joe Biden, who has not yet decided whether to run for president, seems to have a better chance of defeating Republicans in a general election than Clinton.

When the pollsters put Biden up against the same Republicans in head-to-head matchups, he came out on top against each one.

Biden beat Trump, 50 percent to 37 percent, Bush by 46 percent to 41 percent and led Carson and Fiorina by 46 percent to 42 percent.

Florida Sen. Marco Rubio did the best against Biden, only trailing by one point, 44 percent to 43 percent.

Support for Carson has almost doubled in the past two months, and he now trails Trump by only one percentage point and is viewed as ethical by the largest number of voters. He also now has the largest number of GOP primary voters who say they would definitely vote for him, according to Fox.

Trump remains on top with 24 percent, followed closely by Carson at 23 percent and Texas Sen. Ted Cruz in third with 10 percent. Rubio was fourth with 9 percent, former Florida Gov. Jeb Bush with 8 percent, Fiorina and former Arkansas Gov. Mike Huckabee with 5 percent each and Kentucky Sen. Rand Paul with 3 percent.

Among Democrats, Clinton leads with 45 percent, followed by Vermont Sen. Bernie Sanders at 25 percent, Biden with 19 percent and former Maryland Gov. Martin O'Malley with 1 percent.

The telephone poll was conducted among 1,004 randomly chosen registered voters between Oct. 10-12 and has a margin of sampling error of plus or minus three percentage points for all registered voters. The margin of error is five points for both Democratic and Republican primary voters.