It spoiled an outstanding effort from the left-handed Richard, who pitched seven innings of one-run ball. As he's wont to do, Richard lived down in the strike zone, recording 12 outs via the ground ball.
"You trust the man, that's why you give him the ball on the first day of the season," said Padres manager Andy Green. "He was outstanding.
New Padres first baseman Eric Hosmer -- who went 0-for-4 with a walk -- received a rousing ovation during pregame introductions. Shortly thereafter the crowd was whipped into a frenzy for the ceremonial first pitch from newly-elected Hall of Famer Trevor Hoffman.
But Brewers starter Chase Anderson quickly cooled the festive atmosphere with six innings of one-hit ball.
"We pitched really well today," Brewers manager Craig Counsell said. "We've pitched really well for a while now. We haven't gotten a ton of credit for how well we've been pitching, going back to last year."
Freddy Galvis, acquired in a December trade with Philadelphia, salvaged things temporarily for the Padres. His two-out single in the bottom of the ninth tied the game at 1.
"Everything was beautiful for Opening Day," Galvis said. "The fans were great, everything was very cool. I just wish we could've ended it with a win."
After two shutdown frames from Brad Hand, the Padres called on right-hander Adam Cimber in the 12th. A non-roster invite to Spring Training, Cimber earned his way onto the club with a dominant Cactus League showing.
Admittedly, it was a tricky spot for a Major League debut. Cimber allowed three hits, including Ji-Man Choi's two-out double and Arcia's ensuing go-ahead knock.
"I'd put him right back in that situation tomorrow," said Green, who had already used four other relievers at that point.
In reality, it was the Padres' offense that fell short. Richard did his part. The bullpen did its part. And the defense turned three double-plays -- two of the highlight-reel variety in the first two innings.
"If it weren't for our defense, we wouldn't have been in it," Richard said. "They played terrifically out in the field, and they grinded through at-bats. It just didn't turn our way in the end."
MOMENTS THAT MATTERED Stop sign: The Padres had a chance to end the game in the 11th when Jose Pirela's bloop single trickled away from Brewers right fielder Domingo Santana. But Hosmer was held at third base, leaving the game in Chase Headley's hands. Headley smacked a hard ground ball to third base, where Travis Shaw started a 5-2-3 double play.
"Off the bat, I knew nobody had a chance at it," Hosmer said of Pirela's single. "All I was thinking was first-to-third in that situation. Obviously, he bobbled it. ... We just stopped last second. Nine times out of 10, bases loaded with Chase coming up, you don't risk that chance."
Szczur swipes a run: The Padres kept backup center fielder Matt Szczur as one of their final roster decisions this spring. His presence is already paying dividends. Serving as a pinch-runner for Carlos Asuaje, who led off the ninth with a single, Szczur put himself in scoring position with a gutsy steal of second base. He would score two pitches later on Galvis' RBI single.
"For a guy just sitting there all day to come in, get a good read and have the guts to go and be safe, that was big for us," Green said. "It gave us an opportunity to try to win the baseball game."
Welcome Crew: With two outs in the third, Anderson swatted a single to center, and the two newest Brewers made Richard pay. Lorenzo Cain singled and Christian Yelich followed suit with a blooper to left. It landed mere feet in front of Pirela, whose throw to the plate was up the line. Anderson scored -- though his slide wasn't pretty, as he smacked his head against home plate.
QUOTABLE "We're going to score runs. Today wasn't a great day. But if you watch enough baseball in your life, you realize great teams score one run sometimes." -- Green
SOUND SMART WITH YOUR FRIENDS Headley's Opening Day start was his sixth as a Padre (and his first since 2014, after a 3 1/2-year stint with the Yankees). In franchise history, only Tony Gwynn, Garry Templeton and Gene Richards have more starts in the season opener.
WHAT'S NEXT After a dominant Spring Training, Joey Lucchesi will make his big league debut for the Padres on Friday night against Milwaukee at 7:10 p.m. PT. The club's No. 9 prospect, Lucchesi posted a 1.54 ERA in four outings this spring, after recording a 1.99 mark in two Minor League seasons. Clearly, opposing hitters have struggled to solve his funky left-handed delivery.