CHICAGO -- A considerable amount of dirt was caked across the right side of Yu Darvish's silver name plate above his clubhouse locker. It was the result of an anger-fueled heave of his muddy spikes in the moments following Sunday's gut-wrenching loss to the Cardinals.

As Darvish spoke to reporters after the 3-2 defeat -- a fifth straight one-run loss that knocked the Cubs out of contention for the National League Central crown -- the pitcher struggled to find the words to describe his emotions. So Darvish glanced back at his locker and pointed to the residue of his 111th toss.

• Box score

"I'm so frustrated. Worst in my life," Darvish said. "You can see it, right?"

Darvish did all he could to go the distance for a Cubs team that had a bullpen running on fumes and a season hanging in the balance. Working in a steady rain, the right-hander piled up a dozen strikeouts, baffling St. Louis' lineup. When he took the mound in the ninth inning, Darvish had the Cubs positioned for a much-needed 2-1 victory.

And then, it slipped away with one last Cardinals rally.

With their sixth straight loss, including being swept in a four-game series by the Cardinals at Wrigley Field for the first time since May 1921, the Cubs dropped to seven games back of division-leading St. Louis with only six games to play. Three of those games are in a season-ending series at Busch Stadium, where the North Siders had hoped to be fighting for the Central.

Instead, the Cubs will continue to cling to the hope that one of the two teams ahead of them in the NL Wild Card race will hit a serious snag in the final week. Right now, the Nationals and Brewers are tied for the top Wild Card seed, with Chicago trailing by four games.

• NL Wild Card standings

"It's tough sledding, but we've got to win," Cubs first baseman Anthony Rizzo said. "One game at a time and see what happens. That's all we can do."

Compounding matters for the Cubs was the loss of slugger Kris Bryant, who sprained his right ankle after slipping on first base in the third. Bryant had to be helped off the field, though initial X-rays showed no fractures in the third baseman’s foot. An MRI exam is planned for Monday's off-day, and the results are expected to be announced Tuesday in Pittsburgh.

• Bryant injures ankle; X-rays negative

That setback comes with Rizzo playing through a sprained right ankle of his own and Javier Báez dealing with a still-healing hairline fracture in his left thumb.

"It's been tough," Cubs outfielder Albert Almora Jr. said. "It's been a tough, tough series for the boys."

The series with the Cardinals was once-in-a-century tough.

According to the Elias Sports Bureau, Chicago became the second team in MLB history to be swept in a four-game series at home with each loss being a one-run defeat. That had not happened since June 1919 (Cleveland sweeping the Red Sox in Boston). This is also the first time the Cubs have experienced five straight one-run losses since July 1915.

"If you just play back the tape," Cubs manager Joe Maddon said, "it's almost unbelievable that it turned out this way."

Darvish took the mound in the ninth inning at 96 pitches and armed with a 2-1 lead -- provided by a solo homer from Nicholas Castellanos off Miles Mikolas in the sixth. Pinch-hitter José Martínez sent the second pitch he received to deep center field, where Almora sprinted back in an effort to chase it down. The center fielder jumped, reached and the baseball nicked off his glove.

The ball dropped to the warning track and Martínez had a triple.

"You can't catch them all, but I tried," Almora said.

Dexter Fowler used a sacrifice fly to plate the tying run and then Tommy Edman followed with a single and a stolen base against Darvish. That set the stage for Paul Goldschmidt, who yanked a low-and-inside pitch down the left-field line for a go-ahead, run-scoring double.

"That was a good pitch," Darvish said. "That was a ball, almost dirt. But he's the only guy that can see my splitter well. That's why he got it."

That put the final touches on the line for Darvish, who logged 110 pitches and walked none in 8 1/3 innings. He became the first pitcher in Cubs history to have at least a dozen punchouts in three consecutive games, dating back to at least 1908. That feat has only been done 22 times in MLB history.

Darvish’s performance came after he racked up 27 strikeouts across his past two starts -- the most recent one including a single-game club-record eight punchouts in a row.

"You've got our guy throwing as well as a baseball can be thrown," Maddon said. "Forever. I mean, I'll go back as far as you want to go back. That's as well as a baseball can be actually pitched from the mound to home plate. A ball goes off our center fielder's glove and all of a sudden, it's a different ballgame."

Barring a drastic swing in fortunes, October is setting up to be much different than what the core group of this Cubs roster is used to experiencing, too.

"There's no words right now," Darvish said. "Sorry."