Gov. Martin O’Malley’s plan to allow a Las Vegas-style casino in Prince George’s County easily cleared its first legislative hurdle Thursday, just hours after a plea from the owner of Maryland’s largest gambling venue not to undermine its business.

The owner of Maryland Live! and supporters of the Anne Arundel County casino testified before a Senate panel on the first day of a special legislative session and tried to halt the momentum of O’Malley’s plan to expand gambling.

“This additional site will be a boa constrictor that will squeeze the life out of Maryland Live!” Anne Arundel County Executive John R. Leopold (R) told the Senate Budget and Taxation Committee.

With the panel’s 11 to 1 vote, the legislation goes to the Senate, where it will be debated — and likely passed — on Friday. A fight over the bill looms in the House of Delegates, where similar legislation died during this year’s regular legislative session.

O’Malley (D) said Thursday that he is “hopeful” the House will look more favorably this time on his legislation, which also allows table games, such as blackjack and roulette, at the state’s five previously approved slots sites.

Supporters of a Prince George’s facility, including County Executive Rushern L. Baker III (D), have argued there is room for another casino in Maryland that would draw patrons heavily from the District and Virginia.

O’Malley’s plan would invite bids to operate the casino from a swath of Prince George’s that includes both National Harbor and Rosecroft Raceway.

The new site and new games would also require statewide voter approval in November.

Meanwhile, legislative staff released an analysis of the bill that predicted it would net the state more than $200 million a year after a Prince George’s casino opens in mid-2016.

The bulk of the money — about $130 million — would come from other provisions in the legislation, however. Those include the introduction of table games, allowing casinos to stay open 24 hours and transferring responsibility for procuring slot machines. Maryland is one of just a few states where the government, not casino owners, is responsible for buying or leasing the machines.

As O’Malley’s bill is structured, the Prince George’s facility would net the state about $70 million a year, once concessions are granted to other casino owners to compensate them for the new competition, according to legislative staff.

The legislation offers both the Cordish Cos., the owner of Maryland Live!, and the operator of a planned casino in Baltimore an additional 5 percent in revenue, up from the current 33 percent. The two companies also can appeal to a state gaming commission for more relief.

During Thursday’s testimony, Joe Weinberg, Cordish’s managing partner, said the concessions in the bill are far from acceptable. He told senators that his company would have not built such a large casino if it knew a sixth site could be authorized so soon.

Maryland Live!, which opened in June, is expected to have 4,750 slot machines by this fall, making it one of the largest facilities of its kind in the country.

Weinberg also played up the development company’s Maryland roots — it is based in downtown Baltimore — in his appeal to senators.

“We’ve played by the rules,” he said. “We’re a Maryland company.”

James J. Murren, chairman of MGM Resorts, which has been lined up to operate a potential casino at National Harbor, also stressed a Maryland connection, saying that he met his wife in Baltimore.

National Harbor and MGM have lobbied for a casino with more slot machines than the 3,000 that O’Malley’s bill would allow. They also have pushed for a greater share of revenue than the 38 percent that is possible under the governor’s plan.

Outside the hearing room, Murren told reporters that “we’re completely comfortable within the contours of the bill.”

Meanwhile, Penn National Gaming, the company that owns Rosecroft, another possible Prince George’s site, said Thursday that it opposes the bill. Penn questioned whether the bid process in Prince George’s would be fair and said that a Maryland casino it owns in Perryville, in Cecil County, is treated unfairly under O’Malley’s bill.

Senate President Thomas V. Mike Miller Jr. (D-Calvert) told his chamber’s members that he expects to act on the bill either Friday or Saturday. That will shift the focus to the House, which was not in session Thursday.

Miller said he is hopeful that a final bill can be passed by Tuesday night. “I think we’re going to get it done, but if we don’t, it’s not going to be because we haven’t tried,” he said.

Several lawmakers were clearly not thrilled to be back in Annapolis in August for a session on gambling, with a bill to address a court ruling on the liability of pit bull owners also to be considered.

“This whole session is a farce,” said Nancy Jacobs (R-Harford). “I mean, it’s the pits. It’s about pit bulls, pit bosses, and my citizens say it’s pitiful.”