MILWAUKEE -- Jon Lester is not one to ask out of a ballgame. On Saturday night, following seven impressive innings and after overcoming an illness that forced him to skip a start earlier in the week, the veteran left-hander told manager Joe Maddon that he was done.

"I was dead," Lester said.

That moment initiated a chain reaction that rippled through the remainder of Saturday's game at Miller Park, where the Brewers partied on the field after dealing the Cubs a 5-3 walk-off loss in 10 innings. Chicago's bullpen allowed two runs in the eighth, and then closer Craig Kimbrel gave up two homers in the 10th, culminating in a game-winning two-run blast by Keston Hiura.

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And so, the story felt familiar for the North Siders.

A lack of offense put every managerial decision by Maddon under the microscope in a defeat that was one in a long list of road losses this season. The Cubs dropped to 1-4 on their current trip and have lost the first two in a run of nine straight games against the Brewers and Cardinals. St. Louis took over first place on Friday, and now the Brewers and Cubs are tied for second.

"I've never seen anything like this. I feel like we're still playing good ball," Cubs reliever Steve Cishek said. "I have no answers -- I really don't."

The source of Cishek's loss of words was Chicago's ledger away from Wrigley Field this season. The Cubs are 36-18 at the Friendly Confines, but just 19-31 on the road. The biggest difference has been in the pitching and, specifically, the bullpen production. At home, Cubs relievers have a 3.14 ERA. The group has collectively turned in a 5.44 ERA on the road.

Chicago's bullpen has been a storyline since the start of last offseason, and it continues to be a pressing topic with three days left until Wednesday's Trade Deadline. The Cubs have used 22 players in relief this season. Five members of the Opening Day bullpen remain in the big leagues. Pedro Strop has not been right for most of the year. The Triple-A shuttle has been active.

In Friday's 3-2 loss, Chicago allowed three runs across the seventh and eighth innings, losing a slim lead and the game. Saturday's tilt took a similar path. Anthony Rizzo's two-run homer in the third backed seven shutout innings from Lester, who was scratched on Wednesday in San Francisco with flu-like symptoms.

When Lester indicated that he was spent on Saturday, Maddon had a decision to make for the eighth inning.

"It was Cishek's inning. It's very simple," Maddon said. "Cishek was ready to go today."

One night earlier, Cishek logged 26 pitches, walked two batters and hit another in one inning that stretched between the sixth and seventh. The sidearmer said on Saturday that he was fighting his delivery in that appearance and wanted to get back to "attack mode" in his next outing. Instead, it was the Brewers who went on the attack.

Ben Gamel belted a leadoff homer off Cishek in the eighth and then Lorenzo Cain doubled off the wall in center. That led to Maddon shuffling to and fro from the mound and dugout, cycling through Cishek, Derek Holland, Tyler Chatwood and Rowan Wick in the frame.

"I thought Lorenzo's double was really big, because it just made the inning tough for them," Brewers manager Craig Counsell said. "They ended up using four pitchers that inning, and I thought that double set a lot of things in motion."

Holland -- acquired from the Giants for cash on Friday to be a lefty specialist -- did his job by getting slugger Christian Yelich to fly out to center. Two batters later, though, Hiura sent a pitch from Chatwood sharply up the first-base line and into right field for an RBI double that pulled the game into a 2-2 deadlock.

Wick escaped the inning by striking out Eric Thames and then got through the ninth unscathed.

"He showed a lot of guts out there," Cishek said, "and I think he opened a lot of eyes, for sure."

For a moment, it looked like Wick's effort was going to pay off, too.

Albert Almora Jr. launched a go-ahead homer for the Cubs in the top of the 10th -- complete with a bat flip -- to set things up for Kimbrel. This was precisely the kind of moment Chicago had in mind when it signed Kimbrel to a three-year, $43 million contract last month. The heart of Milwaukee's lineup was due up and the Cubs now have one of baseball's all-time great stoppers.

"Once the Cubs signed him, we knew that we were going to get a lot of him," Hiura said.

Yelich led off by hammering an elevated fastball to left field for a game-tying home run. Kimbrel, whose fastball velocity was 94.8 mph on average per Statcast, then walked Tyler Saladino on seven pitches. That set the stage for Hiura, who sent a 1-2 curveball on a line to right, where it disappeared over the wall to set off a mob scene for the Brewers.

"I didn't do what I wanted to do tonight," Kimbrel said. "That's disappointing, obviously. We need to win games like that."