Former Florida state Speaker Marco Rubio, who is touting himself as the true fiscal conservative in the Sunshine State’s GOP Senate primary, on Wednesday was endorsed by Sen. Tom Coburn (R-Okla.), one of the leading fiscal hawks in Congress.

“I have closely studied Florida’s Senate candidates and have no doubt that Marco Rubio is the only fiscal conservative in this race,” Coburn said in a statement. “At a time when Washington is piling on crippling debt on our economy, the American people need Marco Rubio in Washington to stand up to this reckless behavior and offer clear conservative solutions.”

Rubio has made Gov. Charlie Crist’s (R) support of President Barack Obama’s economic stimulus legislation early last year a major topic of the primary campaign. In their first primary debate earlier this week, Rubio repeatedly criticized Crist for supporting the president in that effort. In his endorsement, Coburn also took a shot at Crist on that topic.

“In my lifetime, I’ve never seen as wasteful a spending project as the failed $787 billion stimulus bill that Marco’s opponents supported,” Coburn said. “I have full confidence Marco will stand against costly disasters like the stimulus bill and government-run health care.”

Along with Coburn, other key conservative leaders in Congress who have endorsed Rubio include House Republican Conference Chairman Mike Pence (Ind.), Republican Study Committee Chairman Tom Price (Ga.) and Sens. Jim DeMint (R-S.C.) and James Inhofe (R-Okla.).

The winner of the primary is all but certain to face Rep. Kendrick Meek (D) in the general election.