New Jersey Gov. Chris Christie is the only potential Republican presidential contender who would currently best former Democrat Hillary Clinton in Iowa, according to a survey released Monday by Harper Polling, a Republican firm.

The poll showed Christie winning 43 percent of the vote in a general election match-up with Clinton. The former secretary of state would garner 38 percent support. Another 19 percent of those surveyed were undecided.

Christie and Clinton are both considered strong candidates for their parties' nominations should they choose to run for president in 2016. But Christie would have a more complicated path to the general election than would Clinton.

Clinton, a former first lady, U.S. senator and secretary of state, is the presumptive Democratic front-runner and other Democrats have suggested they would skip the primary fight if she runs. Christie, however, faces the challenge of appealing to conservative Republicans in early-voting states like Iowa.

The survey shows Christie facing a formidable challenge from fellow Republicans, including Sen. Ted Cruz, R-Texas, who burnished his national conservative credentials during the recent congressional showdown over Obamacare that led to a government shutdown. Christie and Cruz are in a dead heat with 18 percent support among Republicans, the poll showed.

But, more than two years from the 2016 Iowa caucuses, a host of other potential Republican candidates are still solidly in the mix. Sen. Rand Paul, R-Ky., and former Sen. Rick Santorum, R-Pa., both received double-digit support in the survey. Rep. Paul Ryan, R-Wis., Wisconsin Gov. Scott Walker, and Sen. Marco Rubio, R-Fla., also performed strongly. Nineteen percent of Republicans polled were undecided.