ST. LOUIS —David Ross’ eyes widened, watching the baseball leave his bat. And if you looked closely, you might have seen his lips moving.

“I was talking to it,” Ross said.

Ross tried to convince his line drive down the left-field line to stay fair. He was persuasive.

Ross’ double in the seventh inning scored Xander Bogaerts for the winning run in Boston’s 3-1 win over the St. Louis Cardinals on Monday night at Busch Stadium in Game 5 of the World Series.

Boston took a 3-2 lead in the Series, which will resume Wednesday night at Fenway Park.

David Ortiz singled in a first-inning run and Jacoby Ellsbury followed Ross with an insurance RBI, as the Red Sox gave Jon Lester plenty of support.

Lester proved his ace credentials with a brilliant 72/3 innings, allowing four hits, one run and no walks. He struck out seven.

“He’s our backbone. He’s our horse out there,” Ross said. “We expect a lot out of him.”

Lester’s only goof was a waist-high fastball to Matt Holliday, who crushed it for a tying home run in the fourth inning.

“I settled back in and got back into a rhythm and things were good after that,” Lester said.

After Holliday, Lester retired 13 of 14 batters.

“We couldn’t get much going. He kept us down,” Cardinals Manager Mike Matheny said. “We just couldn’t stack (hits) on top of each other.

“It came down to a big hit. They got the big hit when they needed it.”

That big hit arrived in the seventh inning, which was the last inning for Cardinals starter Adam Wainwright.

Wainwright had allowed five hits until that point – including back-to-back doubles by Dustin Pedroia and Ortiz in the first inning.

Wainwright began the seventh with his 10th strikeout. Then Bogaerts stepped up and recorded his second single with a grounder up the middle.

“That kid (Bogaerts) is only 21 years old and having at-bats like that against a veteran like Wainwright,” Ross said. “Guys kept throwing at-bats up there.”

Stephen Drew followed with a full-count walk.

Ross stepped up. Wainwright hung a curve to him.

“Luckily, I got something in the zone and it just stayed fair,” Ross said.

Ross, who was considered the backup catcher, has been getting more playing time in the postseason because he not only works well with Lester, but he is hitting. Ross had two hits Monday night.

“Offensively, he’s given us a spark in there,” Boston Manager John Farrell said.

With two outs. Ellsbury singled in Drew to give Boston a 3-1 lead.

Lester came out for the eighth. With one out, he allowed a David Freese double – the first St. Louis hit since Holliday’s homer.

Lester then got Pete Kozma to fly out. St. Louis sent up slugger Matt Adams to pinch hit and Farrell called on closer Koji Uehara.

Uehara struck out Adams on three pitches, and then went through the Cardinals 1-2-3 in the ninth.

Now the Red Sox are one game away.

“You know you’re close, but now it’s the biggest challenge,” Ortiz said.

Ortiz continued his hot Series, going 3 for 4.

Ortiz came up in the first inning with one out, and Pedroia on second base – after doubling on a hanging Wainwright curveball.

St. Louis had been pitching around Ortiz, but Wainwright came at him with an inside fastball on the first pitch. Ortiz turned on it and doubled down the right-field line, scoring Pedroia.

The Cardinals lost two straight home games and now find themselves needing to sweep the Red Sox at Fenway to win the Series.

“We still got two games we can win,” Matheny said. “It’s a great challenge to prove how tough we are mentally. After that, it comes down to execution.

“But most of it is mentality – not buying into stats or odds or predictions.”

Farrell was not making predictions.

“We won’t get too far ahead of ourselves,” Farrell said.

Kevin Thomas can be reached at 791-6411 or:

[email protected]

Twitter: @ClearTheBases

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