Greuel's name was illuminated in lights on the walls of the election night party, on the second floor of the historic Art Deco building that once housed the city's stock exchange. An adult contemporary mix – Don Henley's "The Boys of Summer," Phil Collins' "Easy Lover" – played in the background.
The candidate herself was said to be watching election returns in a room nearby.
Lorraine Morland, 57, sat perched on the edge of the stage to make sure she had a front-row view when Greuel spoke.
"I didn't come to see all these people," she said, waving at the growing number of supporters. "I came to see her."
Morland met Greuel when her 28-year-old son was murdered in 2001 and she sought a reward offer from the City Council. Since then, she said Greuel has been actively involved in Women Against Gun Violence.
"She's always been a supporter of ours. That's the kind of person she is," said the downtown resident.
Morland returned the favor, phone banking and knocking on doors for Greuel's mayoral bid.
"It's a tight situation, but she deserves to win," Morland said. "If she wins, we win."
Martha Hudak, an attorney who lives near the West Hollywood border, said Los Angeles needed to make history by electing a woman mayor.
"It's about bloody time the second-largest city of the U.S.…gets a woman mayor," said the 58-year-old.
She said it was difficult to predict in a low-turnout election whether that would happen, since it depended on which segment of voters turned out.
"Hope springs eternal," Hudak said.
The crowd cheered when the first wave of returns showed Greuel leading in vote-by-mail ballots by 2 percentage points.