CHICAGO -- As the calendar rolls over to September, it’s time for the Cubs to make their final push toward October.

The month didn’t start the way the Cubs wanted, however, as they dropped Sunday’s series finale to the Brewers, 4-0, at Wrigley Field. The loss also dropped the Cubs to four games behind the St. Louis Cardinals in the National League Central, pending the Cards’ Sunday night game against the Reds.

• Box score

“Listen, it’s tough, but I’ve been here before,” Cubs manager Joe Maddon said. “Understand the situation. You’re not going to hear me cry about it. We just gotta take care of our own business starting tomorrow and moving forward.”

The Cubs looked to have a big weekend in store following Friday’s 7-1 victory. Instead, they dropped two straight games, losing ground in both the division and Wild Card standings.

Sunday’s loss, combined with Yu Darvish being scratched from his start with right forearm tightness and an offense that was shut out for the second straight day, leaves a bad taste in the Cubs’ mouth to start the final stretch.

Tyler Chatwood, making a spot start for Darvish, did what his manager asked of him. The Cubs’ swingman out of bullpen allowed just one run on three hits over 3 2/3 innings of work, striking out seven batters and walking four. The only run Chatwood allowed came on a fourth-inning RBI groundout by Orlando Arcia that drove in Ben Gamel, giving the Brewers a one-run lead.

Milwaukee wouldn’t score again until Christian Yelich crushed a three-run homer off Craig Kimbrel in the top of the ninth inning, extending its lead.

“It’s how it is in September. There’s going to be a lot of games like that. That’s how it was last year. We did it too. We did it to them as well,” Yelich said. “It’s just how it works when you get down the stretch. There’s going to be a lot of matchups on both sides when our two teams go at it. There’s a lot of talented players on both sides.”

“I don’t know if you forget about [the loss], but you definitely want to learn from it and understand that tomorrow you can get one game closer,” Kimbrel said. “Down the stretch here, every game is big. If we get on a nice roll, momentum is big, especially going into the playoffs.”

It’s been difficult for the Cubs to keep the momentum going for longer than three games. The club won three or more games just once in August and did not win back-to-back series during the month. Which is something that their rivals in St. Louis have been able to do.

The Cardinals are 9-1 in their last 10 games and have hit their stride at the right time. While the Cubs aren’t scoreboard watching just yet, they are aware what team is playing a better brand of baseball going into the final four weeks of the season.

“Right now, [the Cardinals] are enjoying this moment. We’re not,” Maddon said. “The power of 24 hours can be incredibly good sometimes.”

“We have a lot of matchups with [Milwaukee in September],” Kimbrel said. “Obviously, we didn’t get them this series, but we have to focus on the next one and when we get to the Cardinals, that’s when we’ll worry about the Cardinals.”

Baez banged up but comes out OK

Shortstop Javier Báez left Sunday’s loss with a jammed left thumb and neck discomfort and was replaced by Tony Kemp.

Baez slid into Arcia’s knee while stealing second base in the third inning. Baez was shaken up on the play and initially stayed in the game before being removed. X-rays on Baez’s hand were negative and he is considered day to day.

“During the game, my thumb was getting swollen. It was getting pretty hard to use my glove. It kept getting worse, but I feel good,” Baez said. “The X-rays were negative. Hopefully, I’m ready for tomorrow. If not, I’ll take an extra day and come back after that.”