BOSTON — The Boston Celtics are home, not home free.

Unable to put the finishing touches on the Los Angeles Lakers and wrap up their first championship since 1986, the NBA's best team since November flew back across three time zones yesterday for a Game 6 they were hoping they wouldn't have to play.

But injuries, another big first-half deficit and a sub-par performance by center Kevin Garnett cost the banged-up Celtics, who lost 103-98 on Sunday in Game 5 at Los Angeles and left Staples Center kicking themselves at the missed opportunity.

"Not what we wanted," coach Doc Rivers said of the team's stay in Southern California. "We wanted two more (wins). Obviously, the blanket was that we get to go home, but we really believed that we could win one of these games. We won one and we'll take it, but that's obviously not what we want."

The Celtics weren't at full strength for Game 5, missing center Kendrick Perkins with a shoulder injury. Whether he'll play in Game 6 will be a game-time decision, but Boston expects to have shooting guard Ray Allen available.

He left the arena immediately following Sunday's game because of a "health issue" with his toddler son, Walker, who underwent medical tests Sunday and yesterday. Allen was still at the hospital when the rest of the Celtics arrived in Boston yesterday, team spokesman Jeff Twiss said.

Allen planned to take an overnight flight so he could play today, according to Twiss.

The Larry O'Brien Trophy, given each year to the league's top team, was nearly Boston's on Sunday in Los Angeles. At one point, it appeared to be on its way to the floor for an awards ceremony now on hold. Instead of being hoisted by the Celtics, it was hauled off to LAX and loaded into a jet's cargo hold for the six-hour flight to New England.

Despite the loss, the tradition-drenched Celtics feel good about their chances of winning a 17th title — on the 17th.

"We're one up, with two games to go at home," said Paul Pierce, who scored 38 in Game 5. "It still feels like we have the advantage, and I do feel like we're the better team."

So the 11th installment of Celtics vs. Lakers, the league's signature rivalry and one of the best in pro sports, has at least one more 48-minute episode.

After a 21-year gap between finals meetings, these teams aren't quite ready to part company.

Why would they?

Now five games old, this series has had plenty of drama (Pierce's return from a Game 1 knee injury), history (Boston's finals record 24-point comeback in Game 4), surprises (Leon Powe's emergence as a Game 2 star) and even a little scandal as former referee Tim Donaghy's allegations of fixed playoff games has hung over the finals like a layer of L.A. smog.

The Lakers are trying to become the first team in finals history to overcome a 3-1 deficit to win a title, and they're one step closer. If they can win Game 6 today in TD Banknorth Garden, they'll force a decisive Game 7.

Kobe Bryant and his teammates staved off elimination Sunday by getting more physical with the Celtics, who today will play their record 26th game of this postseason.

Boston is comforted by being at home, where it is 12-1 in the postseason.