Showing continued signs of finding his swing at a critical time, Carlos Beltran delivered a tie-breaking, two-run homer in the fifth inning. A sequence of rookie pitchers then held that lead for Adam Wainwright, ensuring the Cardinals of maintaining their two-game division lead over the Pirates and Reds -- both of whom clinched spots in the postseason on Monday.
"That's a tough Nationals team over there playing hot baseball right now," said Wainwright, now an 18-game winner. "I knew they were going to be hard. [It was] just a great team win. Everybody did their part again."
The Cardinals kicked off their final homestand in front of 39,783 and sliced their magic number for a division title to four. St. Louis inched to within a half-game in the race for home-field advantage, too, thanks to Atlanta's shutout loss.
"I'm happy that right now we have a spot in the playoffs, but we have a lot of games to play and we're not thinking about that," Beltran said. "We want to win the division. That's going to be our main goal."
The Cardinals needed the patchwork of production to make up for a pair of key absences. Allen Craig is still sidelined indefinitely, and Matt Holliday remains on the mend with a back ailment. A late addition to the lineup, left fielder Shane Robinson tied the game at 2 with his RBI single in the fourth.
An inning later, Beltran, hitting in Holliday's customary spot in the lineup, followed a leadoff single with a 413-foot blast off Nationals starter Tanner Roark. The home run was Beltran's team-leading 24th, but also his first since Aug. 24.
"I don't think he feels that he's got extra weight on his shoulders with Holliday and Allen both out," manager Mike Matheny said. "But there are things to make up in there. Someone's got to come through. Not to put it on Carlos' shoulders, but today, Carlos did it."
Though Beltran has maintained that he's felt physically strong all month, his results have been trending upward in recent days. After batting .176 with seven RBIs in his first 14 games of September, Beltran has hit safely in each of the last five. He has six RBIs during that stretch.
"This is the time of year where I'm not thinking about myself," Beltran said. "I'm thinking about trying to help the team any way I can. I know lately I've been scuffling at the plate, but the only way that will go away is by playing and continuing to take at-bats."
Wainwright, facing a team that has the Majors' best record since Aug. 9, would make that advantage stand. Jayson Werth crushed a first-inning curveball for a two-run homer, to which Wainwright answered by scattering only five more hits in a seven-inning start.
By the end of his night, he had established new season highs in innings pitched (236 1/3) and strikeouts (214). He left to a standing ovation in the eighth as he handed two runners over to the bullpen. Wainwright has now finished at least seven innings in 26 of his 33 starts.
"I feel great. I really do," Wainwright said. "I think I'm feeling better now than I did a month ago. This is the time of year when Cardinal baseball, we need to show up every day ready to win a baseball game. We should be over our weak periods and ready for the playoff push."
How successful that push can be will depend upon how the bullpen continues to evolve. Monday presented the first true test for the Cardinals sans a predetermined closer. The Cardinals announced over the weekend that they would be removing a struggling Edward Mujica from the role for at least a while.
Matheny went on to describe the closer's role as fluid, and he illustrated the meaning of that by using four pitchers to cover the final two innings. He started with lefty Randy Choate, who inherited Wainwright's jam and recorded the first out on a sacrifice bunt.
Next came rookie Carlos Martinez, who, three days after collecting his first career save, retired Ryan Zimmerman and Werth on groundouts. Though one run scored when Zimmerman put the ball in play, the lead held.
"It was interesting going in, but I like being in those situations," said Martinez, with catcher Tony Cruz serving as a translator. "Hopefully, I can get more confidence in those situations."
"I don't even know if he realizes what he did," Matheny added. "That was a tough assignment. … That's the game."
Lefty Kevin Siegrist retired the left-handed hitting Bryce Harper on one pitch to open the ninth. Trevor Rosenthal then needed only seven pitches to record the final two outs and pick up his first career save.
"At this point, everybody is just kind of sitting on their toes knowing that people may be asked to pitch in different situations," Rosenthal said. "The guys did a great job tonight pitching in situations they haven't pitched in before."
For the Nationals, the Cardinals dashed their postseason aspirations for a second straight season. A year after being stunned by St. Louis in the NL Division Series, Washington was officially eliminated from playoff contention with Monday's loss.
"I don't feel too good right now," Nationals manager Davey Johnson said. "We gave it a good fight. We just came up short. Now, we are spoilers. It's not over for us. We still have a say in this thing."