MILWAUKEE -- Ryan Tepera wore a look of both bewilderment and frustration on the mound on Monday night. The Cubs reliever had just yielded a go-ahead double to Jackie Bradley Jr., who has been mired in one of baseball's worst offensive seasons.

In a matter of minutes, what had been a tightly-contested battle between division rivals had come unraveled. That it was Tepera on the hill for much of the eighth-inning collapse in a 14-4 loss only compounded the perplexity.

"He's been so good for us," Cubs manager David Ross said. "There's a trust in him, even when he doesn't look quite as sharp."

It was only this past Thursday that Tepera -- part of Ross' three-headed bullpen monster, alongside lefty Andrew Chafin and closer Craig Kimbrel -- had been part of Chicago's combined no-hitter against the Dodgers. That trio is a big reason why the Cubs could make noise in October, if they earn a ticket to baseball's dance.

The loss knocked the Cubs four games back of the division-leading Brewers.

Going into Monday's meeting with Milwaukee, Chicago's bullpen led the Majors in both ERA (2.67) and strikeout rate (29.3 percent). Tepera came into the evening with a 2.43 ERA and 2.00 Win Probability Added (15th in the Majors and seventh among relievers).

"The bullpen's been awesome," Cubs outfielder Ian Happ said. "It's been amazing for them to carry us and be able to give us the performances they've had, all the way through, not just those back three guys."

Maybe that all makes it a little easier for Chicago to consider Monday's eighth inning madness an ugly fluke and just turn the page. That said, there is no erasing some of the unfortunate history made by the North Siders.

According to Cubs historian Ed Hartig, this marked the first time in franchise history that Chicago suffered a 10-run loss after being tied through seven full innings. The previous high was a pair of eight-run losses (June 1, 2013, against the D-backs, and April 27, 1939, against the Reds).

"It was a good baseball game right up there until the end," Ross said. "I thought we played a phenomenal baseball game right there until that bottom of the eighth."

That was not an exaggeration, either.

Kyle Hendricks, who was 8-0 with a 2.25 ERA in his previous eight starts, allowed four runs, but the Cubs' offense rallied back to save him from the loss column. In the seventh, Patrick Wisdom came off a short-manned bench and delivered a two-run, game-tying homer that soared a projected 435 feet to left-center.

Happ belted a two-run homer in the first. The recently walk-averse Cubs drew eight free passes. Kris Bryant turned in a handful of highlight-reel defensive plays while filling in for first baseman Anthony Rizzo, who is day to day with back tightness.

And perhaps the highlight of the drama-filled contest came in the seventh, when Joc Pederson was thrown out at third while trying to hustle there from first on a Happ double. Left fielder Christian Yelich got a throw off to third baseman Luis Urías, who made an emphatic, acrobatic tag at the final second.

"I'd take that gamble every day of the week," Ross said.

Tepera, on the other hand, was no gamble.

Consider that from May 12-June 20, Tepera pieced together 18 straight outings with no runs allowed. In that stretch, the veteran righty relinquished only three hits, piling up 26 strikeouts against two walks in 20 1/3 innings.

The time period cited there came before his last four outings. In that more recent string of games, including Monday, Tepera has now allowed seven runs on five hits in three total innings.

With one out in the eighth, Tepera issued back-to-back walks to Jace Peterson and Keston Hiura. Then came the go-ahead double from Bradley, who had a 39 OPS+ coming into the game.

Things imploded from there. Tepera allowed two more runs while he was on the hill, and had another charged to his line after Trevor Megill gave up the first of a pair of three-run homers (one each to Willy Adames and Hiura). When the smoke cleared, Milwaukee had reached double digits in the frame.

"Guys just grinding out at-bats and keeping the line moving was the big thing," Brewers manager Craig Counsell said. "Those first two walks against a guy that's having a really nice season, they were just great at-bats."

Ross shouldered some of the blame, especially given how much Tepera has worked to date this season. The reliever leads the Cubs' bullpen in innings (37 2/3) and appearances (37).

"I know he's carried a heavy load for us," Ross said. "So, we've got to take a look at that. Just making sure he can still stay sharp, or how much rest he might need."