With a win tonight, Boston will pull within a game of its record 18th NBA title, while the Lakers would be a step away from their second consecutive crown and 16th overall.
Davis helped breathe life back into the C's in Game 4 with 18 points, nine of which came in the fourth quarter. Nate Robinson also came off the pine for 12 points, half of which were in the last period.
The Boston win essentially created a best-of-three series with Game 5 tonight is Beantown. After that, the series will end in Los Angeles.
Davis had eight points in the final frame of the a 91-84 Game 3 loss, but the rest of Boston's bench was held scoreless in the period. It was a much different story in Game 4, as Boston held a 36-27 overall scoring advantage in the last period. The Celtics had 21 points from their reserves in the final quarter.
"I just felt like a beast. I felt like I couldn't be denied," said Davis, who went 7-of-10 from the field. "I have to seize the moment here."
"They're a great scheming team," Bryant said. "They have a strategy in place, and they execute extremely well. I feel pretty comfortable. I wasn't pleased with the way I took care of the ball. I thought I did a horrible job of that, but it's a great defense."
Lakers center Andrew Bynum, who suffered a slightly torn meniscus against Oklahoma City in the first round of the playoffs and had his right knee drained before the finals started, suffered more swelling after Game 3 and was only able to play a little more than 12 minutes.
"We want Andrew out there as much as possible, but it's just a matter of how he's feeling and how much he can do," Gasol said. "But I think we have enough in our bench and in our team to be able to be aggressive and productive out there."
Bynum, the key to LA's interior defense, had fluid drained from his knee again after the Game 4 loss and was encouraged that the swelling had not returned.
"I'm 100 percent sure that I'm playing come Sunday," the 7-footer said at practice on Saturday. "As long as I'm able to be out there and be effective, that's what counts. And I know this game is the biggest game because it can change the whole series."
Bynum managed to play 28 minutes in the opener of the set, 39 in the second game and 29 in the third, recording 40 points and 22 rebounds as the Lakers took a 2-1 series lead. He had just two points, three rebounds and no blocks in the Game 4 setback.
Meanwhile, the stifling Celtics defense may have figured out the Lakers' vaunted triangle offense. Boston held Bryant, who is shooting just 40.9 percent in the series, to just two field goals in the fourth quarter of Game 4, after limiting him to only one over the last 12 minutes of the previous game.
"They don't want me to beat them, so they put three guys there," Bryant said. "Nothing we haven't seen before, it's just when you win those games, like Game 3, nobody talks about that because we take advantage of it. And if you lose the game, everybody talks about that. It's part of the process."
Wary of waking a sleeping giant, Boston coach Doc Rivers tried to temper the talk of slowing Bryant.
"Kobe is pretty competitive from what I hear, so there's no doubt that the more you talk about it, the more the target is on," Rivers said.
The NBA Finals have been deadlocked at two apiece 15 times and the winner of Game 5 has gone on to win the series 19 times. The last time the Finals were tied 2-2 and the Game 5 winner didn't win the series came in 1994 when the Rockets lost Game 5 to the New York Knicks, then won Games 6 and 7 in Houston to win the title.
The 2010 Finals marks the Lakers' 31st trip to the championship series and Boston's 21st appearance with 12 of those overlapping.
Their finals history dates all the way back to the 1958-59 season when the Lakers still called Minneapolis home. Boston and the game's ultimate winner, Bill Russell, dominated the early years of the rivalry. The Red Auerbach-era Celtics took the Lakers all seven times they met in the finals, although the Jerry West, Elgin Baylor-fueled LA clubs did manage to take Boston to seven games on three different occasions.
The rivalry lay dormant for 15 years until Larry Bird and Magic Johnson "saved" the NBA by bringing their own storied college rivalry to the pros. Bird avenged his loss at Indiana State to Magic's Michigan State Spartans in the 1979 NCAA Finals when the Celtics got past the Lakers in seven games to win the 1984 NBA title.
Johnson and his Lakers responded the next season as LA finally beat Boston in the finals for the first time. Magic also won the rubber match two years later before the rivalry went cold again, this time for 20 years as the Celtics struggled mightily in the post-Bird era.
Boston basketball chief Danny Ainge re-ignited things by acquiring both Garnett and Ray Allen before the 2007-08 season. The two All-Stars teamed with Pierce to create the "Boston Three Party" and the Celtics were relevant again. A 17th Boston championship was the result as Garnett and his Celtics got the best of Bryant's Lakers.
A rematch could have been in the offing last season but a knee injury to Garnett derailed any hopes of a Celtics repeat. Instead, LA earned its 15th championship by taking Orlando in five games.
The Lakers and Celtics have combined to win 32 of the NBA's 63 titles coming into this series.
Game 6 of this best-of-seven series is scheduled for Tuesday back in Los Angeles.