It was the first time the visiting team has won a game in 12 meetings between the teams this year.
Phillies ace Cole Hamels, who won the series opener, can pitch Philadelphia into its first World Series in 15 years Wednesday night in Game 5. He'll be opposed by Game 2 loser Chad Billingsley.
Eleven teams in baseball history have come back from 3-1 deficits to win a best-of-seven postseason series - two in the NLCS.
With a runner at first and one out in the eighth, Victorino lined Cory Wade's first pitch into the right-field bullpen to tie the game at 5. Then, after a two-out single by Carlos Ruiz, Dodgers manager Joe Torre called upon closer Jonathan Broxton, the seventh Los Angeles pitcher.
Broxton tried to throw a 3-1 fastball past Stairs, and the 40-year-old left-handed hitter drove it halfway up the the right-field pavilion to put the Phillies ahead.
Broxton, the seventh Los Angeles pitcher, allowed only two homers in 69 innings during the regular season.
The Phillies picked up Stairs from Toronto on Aug. 30. He has played for 11 teams in his career.
The Phillies hit an NL-leading 214 homers during the regular season, and have nine in eight postseason games, good for 17 of their 35 runs.
There were no brushback pitches or other trouble Monday night, unlike Game 3 when the benches and bullpens emptied in the third inning, moments after Dodgers starter Hiroki Kuroda threw a pitch over Victorino's head in retaliation for Philadelphia's high and tight pitches earlier in the series.
Brad Lidge, the Phillies' sixth pitcher, got four outs for his fifth postseason save in five chances, but it wasn't easy.
Lidge, a perfect 41-for-41 in save opportunities during the regular season, entered a game in the eighth for the first time this year, coming in with two outs and nobody on. Manny Ramirez greeted him with a double, and Russell Martin struck out but reached first on a wild pitch before James Loney flied to left.
Lidge retired the side in order in the ninth, giving the Phillies an 85-0 record when leading after eight innings this year, including six wins in the postseason.
The Dodgers scored twice in the sixth for a 5-3 lead. Casey Blake, who struck out in his first two at-bats, greeted reliever Chad Durbin by hitting a 1-2 pitch over the left-field wall for his first postseason homer.
Juan Pierre, making his first start of the postseason, followed with a double and pinch-hitter Matt Kemp walked. Scott Eyre relieved and first baseman Ryan Howard threw wildly past first on Rafael Furcal's sacrifice bunt, allowing Pierre to score and putting runners at second and third. Andre Ethier lined to first and, after Ramirez drew his second intentional walk of the game to load the bases, second baseman Chase Utley snared Russell Martin's liner and turned it into a double play.
The Dodgers took a 3-2 lead in the fifth, scoring twice with Ramirez delivering the key blow. Rafael Furcal walked and Ethier singled before Ramirez lined Joe Blanton's first pitch to left to drive in Furcal, who ran through third base coach Larry Bowa's stop sign and barely beat Pat Burrell's throw home. Ethier scored on Russell Martin's grounder.
The Phillies tied it in the sixth when Howard scored from third on Chan Ho Park's two-out wild pitch. Then, with Joe Beimel pitching and runners at first and third, right fielder Ethier made a diving catch of pinch-hitter So Taguchi's blooper to end the inning.
Jimmy Rollins singled off Derek Lowe to start the game, took third on Jayson Werth's hit-and-run single and scored when Utley doubled on an 0-2 pitch. Werth came home on Howard's infield out to make it 2-0, and Burrell walked before Victorino grounded into an inning-ending double play.
Furcal bunted for a base hit on Blanton's first pitch in the bottom half, popping the ball over the head of charging third baseman Greg Dobbs. Furcal would later score when James Loney doubled on an 0-2 pitch.
Both pitchers settled down after the first, although neither worked a perfect inning until Blanton set the Dodgers down in the fourth.
Lowe, pitching on three days' rest for the fifth time in his career, allowed six hits and two runs in five innings. Blanton also went five innings, giving up seven hits and three runs. Notes: Orel Hershiser, one of the Dodgers' stars in the 1988 World Series, threw out the ceremonial first pitch, to son Jordan. The elder Hershiser, who recently turned 50, won the NL Cy Young Award before being selected MVP of the NLCS and World Series 20 years ago. The Dodgers hadn't won a postseason series since then until this year. ... Ramirez, who entered with 14 hits in 25 lifetime at-bats against Blanton, extended his record streak of getting at least one RBI in league championship series games to eight. He has 29 RBIs in LCS games in his career to rank second all-time, four behind Bernie Williams.