Red Line, Harvard Square’s newest bar and restaurant, opened quietly this past weekend, without the spotlights or discounts one might expect from the bar replacing the Crimson Sports Grille.

The bar’s co-owner, Patrick M. Lee, said the first few days of business have been “encouraging.”

Despite slow dinner and lunch crowds, Lee said the Red Line had busy Friday and Saturday nights, with lines extending out the door.

While the opening means more competition for neighboring pubs, most local bars have laid out the welcome mat for the former owners of Grafton Street.

“We think [Red Line] will help us,” said Amy J. Barry, day bartender at Shay’s, located across JFK Street from Red Line. “Not too many people come down to this end of the Square. It’ll bring people down.”

Lee said he agreed. He said he expects that his venue will help his competitors attract more consumers to share, as Red Line’s expected clientele matches that of others bars in the Square.

Nevertheless, as Friday’s general manager Deborah Dellorto said, sharing customers may come back to hurt the neighbors.

“We lost $800 in sales the night they opened,” she said. “It definitely took away from my business.”

Daedalus owner Lawrence P. Hopkins said he suffered no lost revenue.

“[Red Line’s opening] has had no affect on our business,” he said. “We have a long-standing relationship with the owners. They’re good for the area.”

Red Line was created by the owners of Temple Bar in Cambridge and the new Grafton Street, scheduled to open later this year at the intersection of Bow Street and Mass. Ave.

Red Line is named for its subterranean companion—the subway train that stops in Harvard Square.

“We’ve got the red light over the bar—people who live and work in Cambridge identify with the Red Line as the way they get here,” Lee said. “Plus, we’re underground, something you don’t see every day.”

But Red Line’s distinctly upscale ambiance couldn’t be farther from the T’s sometimes sordid motif.

With hardwood floors, a slate bar and distinctive red light shades, the restaurant’s menu offers New York steak and seared duck for dinner, and sandwiches and salads on its more reasonably priced lunch menu.