The Casino of the Wind is the first phase of a $925-million expansion at Mohegan Sun that will include a 920-room hotel and more stores and restaurants.

AP / Jessica Hill

NEW HAVEN, Conn. — Mohegan Sun, already one of the largest gambling facilities in the world, will open a new casino tomorrow even as the industry struggles to draw customers amid a weak economy and high gasoline prices.

The 64,000-square-foot Casino of the Wind includes a 42-table poker room, more than 650 slot machines and 28 table games. The new space is the first phase of Mohegan Sun’s $925-million expansion, which will include a 920-room hotel and more stores and restaurants when finished in 2010.

“It shows we’re continuing to evolve,” said Mitchell Etess, president and chief executive officer at Mohegan Sun. “We need to do things to make people want to come here and there’s no doubt adding new exciting attractions accomplishes that goal. I think people are really going to be amazed how beautiful and visually stimulating the Casino of the Wind is.”

Mohegan Sun, owned by the Mohegan Tribe, is in Uncasville, in eastern Connecticut about nine miles west of Foxwoods Resort Casino.

The Mohegan opening comes three months after Foxwoods, run by the Mashantucket Pequot Tribal Nation, opened its $700-million MGM Grand. That 30-story, 2-million-square-foot property includes a new casino, hotel, a 4,000-seat performing-arts theater, restaurants run by celebrity chefs, luxury stores, the largest ballroom in the Northeast and new convention space to accommodate thousands.

Both Mohegan Sun and Foxwoods are hoping the new gambling centers will boost business. Both reported decreases in their July slot-machine revenue.

At Mohegan Sun, slots slipped about 14.6 percent or $16.1 million from July of last year, when the casino hit an unprecedented high point as more than $1 billion flowed through its slot machines. Foxwoods posted a 3.2-percent decrease in slot-machine income compared with July of last year, or about $2.4 million.

The casinos had experienced eight months of declines in slot revenue until May, when they went up two-tenths of a percent at Mohegan Sun and 7.7 percent at Foxwoods. The Foxwoods spike was attributed to the opening of MGM Grand.

The casinos have cited rising energy prices, diminished consumer confidence and competition from other casinos.

Clyde Barrow, who directs the University of Massachusetts New England Gaming Research Project, said that while the timing of the latest launch at Mohegan Sun may not be ideal, the project makes sense in the long run. He said the new casino will be in place to capture growth once the economy improves.

Mohegan Sun is reintroducing poker, which it discontinued a few years ago, as the game has grown in popularity in recent years. Its first major poker tournament is planned for October.

The new slot machines add about 10 percent to the 6,000 slots the casino has now. That will provide space for large crowds to gamble, such as when concerts end, Etess said.

The new hotel will meet strong demand, Barrow said, noting that Mohegan’s existing hotel has a 93-percent occupancy rate, compared with 63 percent for Boston hotels.

The new project does not substantially expand gambling, but Mohegan Sun and Foxwoods are trying to become national destinations with more entertainment and convention meeting space, Barrow said. Toward that end, Mohegan Sun is planning concerts by Janet Jackson, Enrique Iglesias and The Who to celebrate its new casino.

A two-story Jimmy Buffett’s Margaritaville restaurant will open at Mohegan Sun next month. The restaurant is the best-grossing restaurant in Las Vegas, according to Etess.

“We’re really looking to create a well-rounded entertainment experience,” Etess said.