Boston ? Keith Foulke knows how to protect a postseason lead.

Foulke finished off another fine effort by Boston’s bullpen Sunday night, preserving a 6-2 victory over the St. Louis Cardinals that gave the Red Sox a 2-0 lead in the World Series.

Boston is two wins from its first title since 1918, and the entire team can thank Foulke and his stellar setup men.

“It’s easy to be consistent when you have guys down in the bullpen like we have. We keep each other in check,” lefty Alan Embree said. “We’ve done well together all year — it’s not just the playoffs. We had a bad game and I think we all just gave ourselves a gut-check and said, ‘Come on boys, we’ve got to roll out.’ We have very disciplined guys down there.”

In the other dugout, the Cardinals are clearly missing the solid middle relief needed to make up for a pair of poor starts.

Foulke entered with a runner on first and two outs in the eighth inning of Game 2. He retired all four batters he faced, striking out two — his latest lights-out performance in October.

“I think he’s starting to get his credit now,” teammate Kevin Millar said. “He doesn’t blow the radar guns away, but he spots his 88 mph fastball as well as anyone in baseball.”

The Red Sox signed Foulke to a $24 million, four-year contract in the offseason. The former Oakland closer went 5-3 with a 2.17 earned-run average and 32 saves during the regular season. But he was really acquired for this time of year.

The right-hander with the nasty changeup certainly has responded. Foulke hasn’t allowed a run in nine postseason games spanning 12 innings.

“I appreciate you bringing that up. That’s always a great sign,” he said sarcastically, rolling his eyes. “I’ve learned from my past playoffs where I didn’t pitch so well. I’m just going out there and trying not to make mistakes.”

Foulke is 1-0 with two saves and 16 strikeouts this postseason. He has yielded only five hits.

The Cardinals haven’t gotten much from their first two starting pitchers, Woody Williams and Matt Morris. Williams was chased in the third inning of the opener after giving up seven runs and eight hits. Morris was lifted in the fifth on Sunday trailing 4-1.