Sometimes you can rely on a player or trainer guarantee of victory (Plaxico Burress and Joe Namath) and sometimes you can't (Big Brown trainer Rick Dutrow at Belmont).

The Boston Celtics can wrap up their 17th league title in franchise history on Sunday night if they can knock off the Los Angeles Lakers in Game 5 of the NBA Finals. And the odds have continued to shrink game-by-game for the Lakers.

It looked like this series would be tied at this point early on in Game 4 on Thursday night. The Lakers completely dominated the Celtics in the opening quarter of Game 4, and actually held a 22-point lead at one point.

Los Angeles finished the first quarter ahead by 21 points, and they took an 18-point lead into the half, all without a single basket from Kobe Bryant.

In the second half the Lakers got a little too comfortable with their lead and watched Boston storm back and make an unprecedented comeback. Boston outscored the Lakers 31-15 in the third quarter and maintained that pressure in the fourth on the way to an amazing 97-91 win as a 7.5-point underdog.

Paul Pierce led the unflappable Celtics with 20 points and seven assists, while Ray Allen added 19 points and nine rebounds. Kevin Garnett chipped in with 16 points and 11 rebounds, and James Posey had a strong game off the bench with 18 points.

The Lakers' leading scorer was Lamar Odom with 19 points and 10 rebounds, but 15 of those points came in the first half. Bryant was held to 17 points, all in the second half, and Pau Gasol also netted 17 points.

Sasha Vujacic, who poured in 20 points off the bench in Game 3, was no help in Game 4 with only three points on 1-of-9 shooting.

With their backs against the wall in Game 5 the Lakers are a 6.5-point favorite at . For the second game in a row the Lakers have seen their opening odds drop after they were set as a 9.5-point favorite in Game 3 and a 7.5-point favorite in Game 4.

If the Lakers can win on Sunday night and extend the series Game 6 will be played in Boston on Tuesday night.