If the 2016 presidential election was held today, Republican contender Carly Fiorina would beat Democratic front-runner Hillary Clinton, according to a new Quinnipiac poll.

Fiorina barely came out on top in the head-to-head matchup with 44 percent support, compared to Clinton's 43 percent.

Retired neurosurgeon Ben Carson also beat Clinton in a matchup, 49 percent to 42 percent. Former Florida Gov. Jeb Bush did too, 44 percent to 42 percent. Clinton, however, managed to beat Republican front-runner Donald Trump, 45 percent to 43 percent.

Vice President Joe Biden, who hasn't announced his candidacy yet, was the strongest of the Democratic candidates when matched up against Republicans, beating Fiorina 46 percent to 43 percent, Bush 46 percent to 41 percent and Trump 51 percent to 40 percent. Biden tied Carson with 45 percent each.

The poll found that most voters believe Fiorina won last week's second Republican primary debate by a long shot, which a recent CNN/ORC poll also found. Twenty-eight percent of respondents told Quinnipiac that Fiorina outperformed Trump, who placed second with 11 percent. Florida Sen. Marco Rubio was ranked third in debate performance with 6 percent.

Trump still continues to lead the overall GOP field, though, with 25 percent support among Republicans and Republican leaners. Retired neurosurgeon Ben Carson follows with 17 percent, and Fiorina came in at 12 percent. Bush was in fourth with 10 percent, and Rubio took fifth with nine percent.

On the Democratic side, Clinton held her ground far out in front of Vermont Sen. Bernie Sanders, 43 percent to 25 percent, respectively. Biden came in third with 10 percent.

In terms of overall net favorability, Carson performed better than any candidate of either party, 48 percent favorable to 16 percent unfavorable. Fiorina was second, 39 percent to 21 percent, and Biden third with 50 percent to 34 percent.

Sanders had positive favorability ratings as well, 35 percent to 28 percent, but Clinton continues to poll in the negative for overall favorability due largely to the ongoing email scandal, with 55 percent viewing her unfavorable compared to 41 percent favorable. Trump was the second most unfavorable candidate, 36 percent to 57 percent.

The poll surveyed 1,574 voters nationwide between Sept. 17-21, and has an overall margin of error of plus or minus 2.5 percentage points. For the 737 Republican respondents, the margin of error is plus or minus 3.6 points, and for Democrats it is plus or minus 4 points.