Hours after winning his primary, Sen. Marco Rubio challenged his Democratic opponent in Florida's Senate race to six debates on Wednesday ahead of the November election.

"In 2010, all three candidates for U.S. Senate — Kendrick Meek, Charlie Crist and myself — agreed that Floridians deserved a discussion and debate about the future of our state and nation that went beyond 30-second ads and TV news soundbites," Rubio wrote to Rep. Patrick Murphy in a letter obtained by Politico.

Murphy, who defeated Florida Congressman Alan Grayson in the Democratic primary Tuesday night, agreed to participate in six debates against Rubio, including one that the two candidates hope to have sponsored by a Spanish-language media outlet.

But the Florida Democrat didn't stop there. "I have a counter challenge: Sen. Rubio, commit to serving a six-year term," Murphy said in a statement released by his campaign.

"Clearly, Marco Rubio doesn't understand that campaigning and debating isn't governing. Floridians deserve better than Marco Rubio, and that difference will be on display in the upcoming debates, including the Leadership Florida debate on Oct. 26," he added.

Murphy's counter challenge comes after Rubio declined to commit to serving a full, six-year term in the Senate if he wins re-election during an interview with CNN earlier this week.

"No one can make that commitment because you don't know what the future's going to hold in your life personally or politically," he said, fueling speculation that he could take another shot at the presidency in 2020. Rubio decided to seek re-election in late June after telling reporters for months that he was looking forward to becoming "a private citizen in January" 2017.

A Monmouth University poll of likely voters in Florida showed Rubio leading Murphy 48 to 43 percent in mid-August. The poll was taken before Murphy solidified his spot as the Democratic Senate candidate in Tuesday's primary.