SAN DIEGO -- With a man aboard and two outs in the first inning Monday night, Blake Snell set about trying to work his way through a clean opening frame. The Mets, with one of the sport’s most relentless lineups, were never going to make that task easy. But Snell sure made things more difficult than they needed to be.

Snell threw breaking balls out of the zone. The Mets didn’t swing. He threw fastballs in the zone. The Mets’ hitters fouled them off. Eventually -- after Snell had walked three straight hitters to force in a run -- he hung a changeup. Eduardo Escobar laced it to right field for a two-run single.

Finally, 43 pitches into his outing, Snell trudged off the mound having thrown what was tied for the most pitches in the first inning in baseball this season and the most by a Padre since Andrew Cashner in 2016. The Padres trailed by three runs in a game they wound up losing, 11-5, at Petco Park.

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“It's not them, it's me -- I've got to put the ball in the zone,” Snell said. “I've got to dominate the zone. If I'm doing that, they've got to swing. … I've got to get better, fill up the zone, and good things will start to happen.”

Snell’s rough first inning set the tone for a rare poor showing from the entire San Diego staff. The 11 runs allowed by Padres pitchers marked the second-highest total this season, and the most since April 12.

Escobar did the bulk of the Mets’ damage. He singled in the first, doubled in the fourth, homered in the eighth and tripled in the ninth -- recording the first cycle in Petco Park’s 19-season existence. In total, the Mets pounded out 16 hits, and their 11 runs were the most for any team in this ballpark since San Diego scored 12 in the home opener against Atlanta.

“Look, they’re relentless,” Padres manager Bob Melvin said. “They make you throw the ball over the plate. And when you do, they’re ready for it.”

There have been times during his Padres tenure when Snell has looked every bit the dominant former Cy Young Award winner he was in Tampa Bay. But those starts aren’t happening frequently enough. And when Snell struggles, it’s almost always for the same reason: He has a propensity to nibble around the zone, despite the fact that he has proven time and again that his stuff is electric enough to beat hitters.

Snell’s erratic first inning nearly earned him a very early hook. Nabil Crismatt was warm in the Padres’ bullpen, and Melvin said he was one batter away from calling for the right-hander. Ultimately, Snell escaped and finished his outing having allowed five runs (four earned) on seven hits over four-plus innings.

“I go out there in the first inning, and it’s 40 pitches, and [the bullpen] is warming up, I’m like, ‘I can’t do this to those guys,’” Snell said. “It was tough, with how I started.”

Rookie right-hander Steven Wilson pitched admirably in relief of Snell, working three scoreless frames in his longest appearance of the season. San Diego briefly climbed back into the game when Luke Voit launched a three-run homer in the bottom of the eighth inning, cutting the Mets’ lead to 7-5.

Voit would be forced to endure a bit of a wait just to be sure he’d homered. The play was initially ruled a double, but after a long review, umpires deemed that the ball had caromed off something beyond the center field wall and bounced back into play.

“I thought, the way it hit, it’s not going to bounce that hard off the top of the wall,” Voit said. “It ricocheted like 20 feet. So I figured it was a homer.”

It wouldn’t end up making much difference. The Padres never got the chance to mount a rally in the ninth. The Mets scored four runs off Craig Stammen and two more off Tim Hill over the final two frames. 

“We found a way to tack on some runs late,” Voit said. “That was big. Unfortunately, it didn’t go our way in the last inning. … That team’s a good team. We’re in a tough stretch, probably playing four or five contenders in a row. But we’re just as good as these guys. We’re going to come out swinging tomorrow.”