Former Republican National Committeeman Sean Mahoney got a boost on Wednesday when Manchester Mayor Ted Gatsas endorsed his campaign to win the 1st district GOP primary.

Gatsas’ move is interesting because he chose to support Mahoney over former Manchester Mayor Frank Guinta, his predecessor and one of the leading candidates in the Congressional primary.

Guinta was recruited early on by national Republicans to run against Rep. Carol Shea-Porter (D), but his campaign suffered from early stumbles.

Mahoney’s campaign will begin running a TV ad today that highlights the high-profile endorsement and features Gatsas praising Mahoney, according to a report in the Manchester Union Leader.

Gatsas is a former state Senate President and former Manchester alderman.

“He’ll be a critical source of advice and counsel during this primary,” Mahoney said.

But the New Hampshire Democratic Party released a statement mocking the Gatsas endorsement, noting that many of the mayor’s endorsed candidates have ultimately lost.

“The notion that Mayor Gatsas can deliver votes for a Republican candidate is laughable,” Mike Brunelle, executive director of the state party and Manchester Democratic Party chairman, said in a statement. “Candidates that Ted Gatsas has supported have a win-loss record that even the New Jersey Nets and Baltimore Orioles would be embarrassed of.”

Among the other Republicans running in the Sept. 14 primary is defense contractor Rich Ashooh.

The national GOP considers Shea-Porter one of its top targets this cycle.