(AP) -- The St. Louis Cardinals have put themselves in prime position to secure the NL's second wild card by taking advantage of a stretch of games against baseball's two worst teams.
From here on out, the competition will be much stiffer.
The Cardinals conclude the season with back-to-back home series against baseball's two best clubs, beginning Friday night when they face a Washington Nationals team still trying to lock down the NL East.
St. Louis' magic number to clinch a playoff spot and defend its World Series championship is four over the Los Angeles Dodgers with six games to play.
The Cardinals (84-72) have created some separation in the race by winning five of six over hapless Houston and two of three from lowly Chicago since Sept. 18. Prior to this run, St. Louis had lost eight of 11, which included dropping three of four in Washington from Aug. 30-Sept. 2.
Wins could again be hard to come by for the Cardinals, with their remaining games against Washington and NL Central-champion Cincinnati - the two teams trying to clinch home-field advantage throughout the playoffs.
"We have a tough homestand coming up," Chris Carpenter told the Cardinals' official website after Wednesday's 2-0 loss to the Astros. "We have to go back there and win some ballgames, so that we have some momentum going into the wild card, if we get there."
Although the Nationals (95-61) own baseball's best record, they still haven't assured themselves of avoiding the wild card. They have a magic number of three to clinch their first division crown, leading Atlanta by four games with six to play.
"We have to keep fighting," said Gio Gonzalez, who became the majors' first 21-game winner with Thursday's 7-3 victory over Philadelphia. "It won't be easy. We just want to do what we've been doing all year."
What the Nationals have done to get to this point is win with their pitching. The NL leaders with a 3.29 ERA, they held St. Louis to four runs in their three wins earlier this month.
Edwin Jackson (9-10, 3.77 ERA) shut down his former team in an 8-1 victory in that series opener, allowing an unearned run and four hits with 10 strikeouts over eight innings. Yadier Molina was hitless in two at-bats after going 7 for 8 in prior matchups with his former batterymate, who made four postseason starts for the Cardinals during last October's World Series run.
The veteran right-hander had a 7.47 ERA in his three starts following his mastery over St. Louis before yielding one run and six hits over eight innings in last Friday's 4-2 loss to Milwaukee, though he didn't get the decision.
St. Louis counters with Adam Wainwright (13-13, 4.02), who gave up four runs and six hits over seven innings in Saturday's 5-4, 11-inning victory over the Chicago Cubs. Wainwright, whose last victory came in Cincinnati on Aug. 26, is 0-3 with a 6.41 ERA in his last five starts after sporting a 1.47 ERA in winning his previous five.
His winless stretch started in the nation's capital Aug. 31, when he was knocked around for six runs and nine hits in a season-low 2 2-3 innings in a 10-0 loss. Jayson Werth and Ian Desmond each had a pair of hits off the righty.
Werth is batting .351 with three homers and eight RBIs in his last nine games versus the Cardinals, while Desmond is a lifetime .421 hitter in St. Louis.