ST. LOUIS -- David Ross has no illusions about his hitting ability.
"There's a reason I'm hitting sixth, seventh or eighth in the order," the Boston Red Sox's backup catcher said. "It's because I'm not very good at hitting."
However, the guy who batted just .216 during the regular season saved arguably the biggest hit of his career for Game 5 of the World Series on Monday night.
Ross snapped a 1-1 tie in the top of the seventh inning with an RBI ground-rule double, lifting his team to a 3-1 win over the St. Louis Cardinals and a 3-2 lead in the best-of-seven series.
Boston can clinch Wednesday night in Fenway Park, where John Lackey will pitch against Michael Wacha, who has four wins in as many postseason starts for the Cardinals. Game 7, if necessary, would be Thursday in Boston.
Jon Lester dominated St. Louis for the second time in five days, allowing just four hits and a run over 7 2/3 innings. He walked none and struck out seven while earning his second win of the series. Lester pitched 7 2/3 shutout innings during Boston's 8-1 victory in Game 1.
His batterymate supplied some unexpected help against Cardinals ace Adam Wainwright with Xander Bogaerts at second and Stephen Drew on first in the seventh. Behind 1-2 in the count, Ross lined a breaking ball just inside the left field foul line, and it bounced into the seats as Bogaerts trotted home with the go-ahead run.
"Wainwright is one of the top pitchers in baseball," said Ross, who went 2-for-4 on the night. "I think he threw me a backup curve, and it felt good coming off the bat."
Ross had just 102 at-bats during the regular season, missing two months after suffering a concussion when he absorbed two foul tips in a 10-pitch span. He is contributing in the postseason, though, batting .286 in 21 at-bats and working well with his team's pitchers.
"He's swung the bat better in postseason than at any other time," Red Sox manager John Farrell said. "And the rapport he and Lester have refined ... they are great together."
Later in the seventh, Jacoby Ellsbury added insurance with a two-out RBI single, ending Wainwright's night after seven innings. The big right-hander allowed eight hits and three runs, walking one and fanning 10, but he couldn't match Lester's shutdown pitching.
"Waino threw a good game for us," St. Louis manager Mike Matheny said. "They got the big hit when they needed it, and we couldn't put much together."
Koji Uehara retired all four batters he faced for his seventh postseason save. He fanned Matt Adams on three pitches to end the eighth with David Freese at second after a one-out double, and he mowed through the top of the order in the ninth.
Early on, Boston's David Ortiz made another big impact, ripping an RBI double in the first inning to score Dustin Pedroia. The Boston designated hitter-turned-first baseman went 3-for-4, increasing his World Series average to an otherworldly .733 (11-for-15).
"He's in a really good place, obviously," Farrell said of Ortiz.
Ortiz's hit was the last time the Red Sox made contact with Wainwright until the third. Wainwright struck out the side in the first two innings and had eight whiffs through five innings.
St. Louis put Allen Craig, who hadn't played in the field since Sept. 4 because of a foot sprain, at first base to provide an extra right-handed bat against Lester. However, Craig limped into a 6-4-3 double play to end the second inning and grounded out in his other two at-bats.
The Cardinals found some offense in the fourth when Matt Holliday lined his and the team's second homer of the Series over the center field wall to tie the score at 1. That was it for a St. Louis attack that has produced 13 runs in five games.
Matheny said his team's task Wednesday night is simple.
"We just play our game," he said. "If we go about it the right way, we'll be right where we want to be."
NOTES: Bogaerts and St. Louis 3B David Freese each had two hits. ... Boston's first strikeout Monday night was its 143rd of the postseason, setting an all-time major league postseason mark. The 2010 San Francisco Giants, who beat the Texas Rangers in five games to win the World Series, whiffed 142 times. At the end of Monday's game, the Red Sox's total this postseason was 156. ... St. Louis' 4-2 loss in Game 4 represented its first defeat in nine games this postseason when scoring first. ... Cardinals C Yadier Molina played his 20th career World Series game Monday night, second only to New York Yankees SS Derek Jeter (38) among active players.