Opera Ball gala guests were thrilled to find Renee Fleming mingling with guests at cocktails.

Hilton Chicago, home of Lyric Opera’s Opera Ball since 1960, would have had plenty of space for this year’s party, held Saturday night.

If it weren’t for those Chicago Marathon banners in the lobby.

“The Hilton is a beautiful setting that has worked forever,” says Caryn Harris, Opera Ball chair. But the Hilton, headquarters for Sunday’s run, was festooned with marathon-related paraphernalia that, to Ms. Harris’s eye, would ruin the opera ball’s elegant feeling.

“We thought, ‘do we work with all these banners, or do we seize the day and try something new?’” she recalls. “We decided to change the venue and try something new.”

Rather than pick a stylistically similar hotel, say the Palmer House, Ms. Harris and her planning committee chose Jeanne Gang’s Radisson Blu Aqua, which opened in 2007, for this year’s opera ball.

Ms. Harris knew it was a gamble, as the circa-1927 Hilton has the same yesteryear-Chicago glamour as the circa-1929 Civic Opera House. Yet she threw caution to the wind. “If you’re going to change, change,” she said.

The evening started at the opera house with a riveting, intermission-free performance of Richard Strauss’s “Elektra.” After, 640 opera fans who had bought a ticket for the opera ball boarded trolleys to travel 1.7 miles, and eight architectural decades, to the sleek, cool confines of the Radisson.

Heffernan Morgan, longtime Lyric event decorators, fitted the Radisson ballroom with square tables, the better to fit those 640 guests into the room. Tall tree-like vases of cotoneaster branches and contemporary square candle holders shared space with classic white-and-gold china.

After dinner guests were seated, they witnessed Lyric’s traditional Grand March of the Stars. Trumpets sounded as the evening’s key characters, including Anthony Freud, Lyric Opera general director; “Elektra” director Sir David McVicar; conductor Sir Andrew Davis; and Elektra herself, soprano Christine Goerke, entered the ballroom.

At least two Opera ball tradition, trumpets heralding opera-ball guests, did not survive the move, as the Radisson has neither balcony or winding staircase to accommodate the trumpeters. Instead, guests walked an L-shaped red carpet, dramatically lit by a glowing “Lyric Opera of Chicago” screen, as they entered the Radisson.

Guests reacted differently to the change, especially the noisy, crowded cocktail hour.

“I just want a Diet Coke,” said Joanne Brooks, president of Creative Impact Group Inc. in Chicago as she tried to maneuver into the thick line of people waiting at the long, narrow bar. A few minutes later she returned, Coke-less. “I give up,” she said.

“I think it’s wonderful,” said Ruth Ann M. Gillis, a Lyric board member and executive vice-president, chief administration and diversity officer at Exelon Corp. The Radisson’s home, the Jeanne Gang-designed Aqua Tower, “is significant, just like the opera building,” Ms. Gillis pointed out.

At press time, Lyric Opera did not have net proceeds for the evening available.