ST. LOUIS -- The Cardinals took advantage of key defensive errors committed by the Nationals on Tuesday, but it wasn’t enough in a 6-2 loss at Busch Stadium.

The Cardinals knew going into this pivotal series that they would be facing the Nationals’ triple threat of Stephen Strasburg, Patrick Corbin and Max Scherzer. Yet after beating Strasburg on Monday, St. Louis swung hard against Corbin without many results on Tuesday. The Cards struck out 14 times and went 0-for-9 with runners in scoring position.

• Box score

Despite the loss, the Cardinals maintained their two-game lead in the National League Central, though both the Cubs and Brewers are now just two back, thanks to Milwaukee's victory over the Padres. What was a 4 1/2-game lead less than a week ago has shrunk at a crucial time, with the Cards set to play a four-game set against the Cubs at Wrigley Field following Wednesday's series finale against the Nationals.

The Cardinals’ offense has struggled with consistency all year, but it’s been magnified over the last week. St. Louis was held to one run in back-to-back games on Sept. 10-11, but then exploded for 10 runs in each of its next two games. On Tuesday, the only runs the Cardinals scored were unearned. Part of it was the pitcher they were facing and part of it was not coming through with one big hit -- especially with runners on base.

“When guys are executing pitches, that’s a tough ask,” Cardinals manager Mike Shildt said. “That’s not a recipe for a lot of high numbers of scores. We do what we can to scratch and claw ... but it’s a combination of those guys being over the plate and us letting them a little bit.”

Two specific at-bats Tuesday highlighted the Cardinals’ struggles in both facing a pitcher’s best pitch and not producing with runners in scoring position.

Molina’s bases-loaded strikeout

The Cardinals worked Corbin hard in a few innings, including the third, when they forced him to throw 31 pitches. They tied the game when Trea Turner bobbled Paul DeJong’s bases-loaded grounder, allowing Miles Mikolas to score and leaving the bags full for Yadier Molina.

Molina worked a 2-2 count before chasing a slider at his feet to end the threat. Corbin’s slider fooled the Cardinals all night -- they swung and missed at 17 of those offerings, and eight of Corbin’s 11 strikeouts came on the slider.

The Cards planned for the slider, but they were deceived by its break and spin. Paul Goldschmidt, who was teammates with Corbin for seven years on the D-backs, was the only Cardinal to get on base multiple times against the lefty. He had a double and worked two walks.

“It's just hard to pick up,” Goldschmidt said. “It comes out looking just like his fastball. It doesn’t go up or to the side and break. It just comes out and it’s straight for a longer part of the pitch -- I don’t know if it’s halfway to the plate or two-thirds or whatever -- but it seems like it’s late-breaking, and at the last second, it breaks. That’s basically what guys who got to first base would say to me when I was on his team. You know it going in, but there’s a reason he’s been successful for as long as he has.”

DeJong’s grounder strands two

Goldschmidt and Marcell Ozuna were able to lay off of Corbin’s slider with two outs in the fifth to put runners on first and second for DeJong. DeJong hit a two-seam fastball from Corbin hard -- it had a 101 mph exit velocity, according to Statcast -- but it was a grounder right to Turner, who forced out Ozuna at second for the third out.

DeJong is hitting .167 (3-for-18) with runners in scoring position since Sept. 1.

“It’s about getting a good pitch to hit and putting a good swing on it,” Shildt said. “Not trying to do too much. The guys are trying to be aggressive, and we always appreciate aggression. But we also want to make sure we’re being patient with it, as well, and use the whole field.”

It’s hard to balance where to place the blame when a hitter doesn’t come through with runners on base. Do you chalk it up to the pitcher executing a pitch, or do you look at the approach of the hitter?

Goldschmidt says it’s a little bit of both.

“I think you have to evaluate each at-bat by itself,” he said. “It’s hard to say you can have a good at-bat and still get out, but there are other times where you have to take ownership of your at-bats and say, ‘Maybe I was too patient or maybe I did this or whatever.’

“It’s no different than with nobody on or just a guy on first or something like that. But I think you evaluate all your at-bats as an individual -- and somewhat as a team -- but it’s a little individualized, too. You have to be honest with yourself.”