The Nets fought back from a three-games-to-one deficit against the Chicago Bulls to earn this opportunity, a win-or-go-home game in their new arena and another chance for their black-clad fans to shower this rebranded franchise with full-throated adoration.

They were confident because it was all right there, all on a platter, all for the taking. The Bulls’ roster had been thinned by injury and illness. The Nets could surge into a second-round series with the top-seeded Miami Heat.

But it all crumbled to pieces in a first-half performance that, for the Nets, could not have been scripted any worse. The Bulls went on to win, 99-93, on Saturday night, closing the inaugural season at Barclays Center with an anticlimactic thud and cutting short the season of a team with designs on a deeper postseason run.

“When we won Game 6,” Nets point guard Deron Williams said, “we felt like this was our series.”

In front of a raucous capacity crowd — the first to watch a Game 7 in Brooklyn since the Dodgers hosted the Yankees in 1956 — the Nets shot 40.7 percent and fell behind by as many as 17 points in the first half. They closed the gap to 4 in the fourth quarter, but Chicago, which scored 52 points in the paint and had 19 offensive rebounds, managed to hold on.