SAN DIEGO -- Yasmani Grandal's bat was in demand.

The Brewers had been scuffling offensively. One of their best hitters was on the bench because of injury. No way was manager Craig Counsell going to go without another of his power threats and put Grandal on the bench just because it was a typical rest situation for a starting catcher -- a day game after a night game.

So Grandal played first base Wednesday afternoon at Petco Park.

The bat delivered, as Grandal hit a go-ahead three-run homer in the seventh inning. But his inexperience at first base showed at an inopportune moment as the Brewers suffered a frustrating 8-7 loss to complete a three-game sweep at the hands of the Padres.

• Box score

Milwaukee finished its eight-game road trip with a 2-6 mark. The Crew will be back home Thursday to open a four-game series vs. Cincinnati.

“Tomorrow’s another day,” Grandal said. “We’ll just have to turn the page, finish the first half strong. It’s not the end of the world.”

For a while, it appeared Grandal had given the Brewers a happy flight home. He pulled a 96.8 mph fastball from Gerardo Reyes over the right-field wall for his three-run homer and a 7-5 Brewers lead.

But the Padres answered with a three-run homer by Franmil Reyes in the bottom of the seventh. That inning started with Manny Machado’s high popup falling about halfway up the first-base line. Pitcher Jeremy Jeffress deferred to his fielders, but neither Grandal, second baseman Hernán Pérez nor catcher Manny Piña touched the ball.

Jeffress issued a walk to Hunter Renfroe before Reyes connected to make the missed popup a costly one.

“It was probably Yaz’s inexperience a little bit,” Counsell said. “He got a late break on it. It’s the first baseman’s ball.”

Grandal has 41 big league starts at first base but only eight in the past five seasons. He has started there three times this season, including twice on the road trip. He said any inexperience at the position wasn’t an excuse for letting the popup fall.

“It was a bad case of miscommunication,” Grandal said. “I should have taken over right away. It was my ball. I have priority. We couldn’t communicate.”

That play was but one frustration for the Brewers -- “That was not the game, by any means,” Counsell emphasized -- as their bats woke up on the same day right-hander Zach Davies struggled to spot his sinker and had his shortest start of the season -- 2 2/3 innings, five runs, nine hits and three walks.

The Brewers totaled a single run in the first two games of the series, but Christian Yelich and Ryan Braun joined Grandal in going deep Wednesday. Yelich’s Major League-leading 27th homer was a 447-foot shot to right on a Matt Strahm changeup in the fifth inning that came off his bat at 112.6 mph, according to Statcast. It was his second-hardest-hit homer since Statcast began tracking in 2015 and his longest of the season.

Six more balls came off Brewers bats in excess of 100 mph, only to result in outs. Seven runs produced while Mike Moustakas was limited to pinch-hit duty because of a left hand bruise surely will help the offense get into a better mindset heading home, but a few of those hard outs finding the right spot could have sent the Crew home with a win as well.

“It’s a frustrating trip,” Counsell said. “You lose a couple 8-7 games, and we had leads in both those games. ... This series is just a frustrating series. Nothing felt like it went right these three games. Part of it is we’ve got to make things go right.”

One thing did go right. In the second inning, the Brewers benefited from a Petco Park ground rule and Eric Hosmer’s assumption that Machado’s 403-foot drive to left-center was a home run.

With Fernando Tatis Jr. on third and Hosmer on first, Machado hit the long drive. The ball landed atop the fence, hit a second row of padding for ad panels on the back side of the fence and bounced back onto the field of play.

Center fielder Lorenzo Cain hustled the ball in to third baseman Travis Shaw, who tagged Hosmer as he jogged around the bases. The umpires never signaled home run, however. After the umps conferred and then went to replay review, the call of no home run was confirmed. Tatis scored, Hosmer was out and Machado was placed on second base, officially credited with a single because Hosmer never reached third.

“The umpire didn’t signal homer, so I just tagged him out,” Shaw said. “It was not a homer, so I tagged him.”

Said Counsell: “We caught a break. I mean, Hosmer stopped running. We caught a big break there.”