BOSTON – As the legend goes, Bill Russell walked into the L.A. Forum for Game 7 of the 1969 NBA finals and looked above him. Thousands of balloons were suspended over the court by netting in an optimistic arrangement that was meant to shower the court when the Lakers won the championship.

Russell wasn’t having it.

Of the 17 NBA titles owned by the Celtics, that one might be their most satisfying because of the opponent and the venue. If Boston can get one win in either of the next two games at Staples Center, that’ll be two rings to savor.

“Yeah, definitely,” said Rajon Rondo, who continues to give the Lakers fits as a matchup problem. “It would be something special because it is the Lakers, the history that these two franchises have had in the past couple of years and almost a century. It would be great to get a win against the Lakers.”

It’s actually more like a half century, but at 24 years old, you can’t expect Rondo to have any historical perspective on this.

What matters to him and the rest of his team is that they know they can beat the Lakers. They know from the experience in 2008, when they brought a 3-2 series lead back to the Garden for Game 6 and rolled to a dominant 131-92 win. At this point, do they own a mental edge?

“Only until we win the fourth game can I answer that question,” Rondo said. “It’s still anybody’s series. … I’m sure they’re going to come out and fight hard, so it’s not over.”

Celtics Coach Doc Rivers recalled the 1994 finals when he was with the Knicks, who took a 3-2 lead to Houston for Games 6 and 7 and failed to finish the job.

“I thought about that the other day when John Starks called me and reminded me of that,” said Rivers, who did not play in the playoffs that season because of a knee injury. “We had our opportunities, obviously, in Games 6 and 7,” Rivers said of that series, in which Hakeem Olajuwon blocked Starks’ potential winner in Game 6, then in Game 7, Starks shot a nightmarish 2 for 18. “You know, that’s a bitter memory for me. I was injured and sitting on the bench.”

Rivers called it “a learning experience” for him, but said it isn’t something he can translate to his players. “Half of them are too young to remember,” he said, “and half of them probably don’t care.”

But when you put on the green, you care about winning titles and even more about winning them against the Lakers, who are currently two titles behind the Celtics for the most in NBA history.

For Paul Pierce, who is from Los Angeles, it’s also an opportunity to win a title in his hometown. “I’m not going to try to jinx it right now,” Pierce said. “We’ve got to win one game, that’s the goal.”

Still, everybody from Kobe Bryant to the Lakers’ bedraggled bench plays much better at the Staples Center.

“If you look at it, they’ve come home and carried the 3-2 lead back,” Lakers Coach Phil Jackson said. “It’s basically home court, home court. Now we’re going back to home court to win it. That’s the way it’s supposed to be, isn’t it?”

Sure, on paper. But two straight losses in Boston led to the dire series deficit for the Lakers, who hadn’t even trailed in any playoff series this season. The Celtics have won three of the last four games, and they’re responsible for Los Angeles’ only home loss of the playoffs.

So why didn’t Jackson or Bryant seem particularly worried before they headed out on their final cross-country flight of the postseason? Throughout a trying season filled with injuries and big-game setbacks since a Christmas Day loss to Cleveland, the Lakers have always been able to rise when they needed to do it.

Jackson even described the Lakers’ locker room as “spirited” after losing Game 5 in their lowest-scoring performance of the postseason in the 92-86 loss. For all their struggles in Boston, the Lakers realize they only have to defend their home court to win their 16th title.

“We have a challenge, obviously, down 3-2,” said Bryant, who scored 38 points in Game 5 while his struggling teammates only managed 48. “We let a couple opportunities slip away, but it is what it is. Now you go home, you’ve got two games at home that you need to win, and you pull your boots up and get to work.”

Yet two straight losses have frazzled the Lakers a bit, with Bryant noticeably furious on the court while Game 5 slipped away. Even Jackson seemed a bit testier than his usual placid self, yelling at Bryant and Ron Artest during the game.

Jackson likely senses the biggest danger yet to his streak of 47 straight playoff series victories after winning Game 1. The Celtics sense a golden opportunity for their 18th title and a chance to join the Boston greats who won multiple titles while repeatedly denying the Lakers nine previous times in the NBA finals.

“The Lakers … got homecourt advantage, but we’ve played the best all year on the road,” Rivers said. “We’re going to have to beat them at their best, because they’re going to be great there, and we can’t expect anything else.”