Fresh off last week’s GOP primary victory, Ohio Treasurer Josh Mandel announced Monday the backing of Sen. Marco Rubio (Fla.), the first-term Republican’s first Senate endorsement of the 2012 cycle.

Mandel said in an email to supporters that starting Monday, he and Rubio would “criss-cross the state, making stops including Columbus, Dayton and Cincinnati.” The latter two stops were scheduled to include small-dollar fundraisers.

They were set to appear Monday night at the Wright State University Nutter Center in Dayton and this morning at the Crowne Plaza Hotel Cincinnati North, charging $25 for general seating at both.

Mandel is challenging Sen. Sherrod Brown (D), who is currently favored to win a second term.