MASHANTUCKET (AP) — Connecticut Republicans began forming their November election ticket on Friday, tapping a former mayor of Meriden to run for the state's open 5th Congressional District seat and a Hartford business owner to challenge U.S. Sen. Chris Murphy.

Manny Santos, a 49-year-old analyst with the United Health Group, won the support of 135 delegates on the first day of the two-day state Republican convention at Foxwoods Resort Casino. But retired university professor Ruby O'Neill garnered 97 votes, enough to participate in the Aug. 14 primary.

O'Neill, the wife of veteran Republican state Rep. Art O'Neill of Southbury, said she will challenge Santos — something he had hoped to avoid.

"It would be nice to go right into the general election without a primary. It saves a lot of time, effort and resources, and money that we actually need for the general election," Santos said. "But on the other hand, this is our system."

The western Connecticut district is considered the GOP's best chance of winning a congressional seat in November. Besides having a relatively close partisan makeup, it acquired an open seat after Democratic U.S. Rep. Elizabeth Esty announced she would not seek re-election following criticism over her handling of sexual harassment allegations in her congressional office.

The remaining four incumbent Democratic U.S. House members are running for re-election. Also, Democratic U.S. Sen. Chris Murphy is running for a second term.

Republicans also endorsed Jennifer Nye of Manchester for the 1st District, Dan Postemski in the 2nd, Angel Cadena for the 3rd and Harry Arora in the 4th.

An expected contest in the 2nd District of eastern Connecticut was avoided. State Rep. Kevin Skulczyck, R-Griswold, was nominated, then withdrew and endorsed Postemski to challenge U.S. Rep. Joe Courtney, who was elected in 2006.

Postemski, 32, a diesel mechanic and a Marine who saw active duty in Iraq in 2004 and 2006, did not shrink from his lack of experience in public office.

"I understand that I am an unknown quantity," he said. "But I am a Marine, and I am a fighter."

Postemski said his campaign will focus on the need to preserve Second Amendment rights against growing pressures. Democrats in Washington "are trying to say that anything that is semi-automatic is an assault weapon," he said.

Santos has been in the 5th District race since February, while O'Neill made her announcement in late April.

"I announced my candidacy before it became easy," Santos said. "I knew that this seat could be won by a Republican. ... We need representatives in Washington, D.C., that support this president's agenda, and I intend to do that."

National odds-makers have predicted the district likely will remain in Democratic hands. The party is scheduled to endorse its candidate on Monday. But JR Romano, the state's Republican Party chairman, has said he believes voter dissatisfaction with how the state of Connecticut is being run by Democratic politicians will help the Republican candidate ultimately win. Romano also is heartened by the partisan makeup of the 41-town district, which borders both New York and Massachusetts. As of April, there were 132,782 Democrats; 100,368 Republicans; and 177,749 unaffiliated voters in the district, according to the Secretary of the State's Office.

Republicans on Friday also endorsed businessman Matthew Corey for the U.S. Senate. The 54-year-old Navy veteran owns a Hartford pub and a window cleaning business. He has previously been an unsuccessful candidate for the 1st congressional district. Dominic Rapini, a national accounts manager for Apple computers, won enough support to challenge Corey in the Aug. 14 primary. He said he'll decide in the coming days whether he'll wage a primary campaign.

For the state's underticket, the GOP endorsed Pomfret nurse and attorney Susan Hatfield for attorney general and former New Fairfield First Selectman Susan Chapman for secretary of the state. Hatfield may face a primary challenge by former state Rep. John Shaban of Redding.

Saturday is expected to be the main event of the state convention. That's when more than 1,000 delegates will endorse a candidate for governor. The field is a crowded one, considering Democratic Gov. Dannel P. Malloy is not seeking a third term. But it got a little smaller on Friday, when gubernatorial contender and New Britain Mayor Erin Stewart announced she will run instead run for lieutenant governor, acknowledging she didn't have enough delegate support.

"When the numbers don't work in your favor, they don't work," she said.

Besides governor, delegates on Saturday also will endorse candidates for comptroller, treasurer and lieutenant governor.

Given the close partisan make-up in the General Assembly and the large number of Republican city and town leaders, GOP leaders are optimistic about their chances in November.

House Minority Leader Themis Klarides, R-Derby, urged delegates to build a Republican team of candidates that have "the guts, the backbone" and fearlessness to push forward the Republican vision. "We all have to feel in our heart and our gut that there is hope for Connecticut," she said.

The Connecticut Mirror contributed to this story.