PITTSBURGH -- The Padres were locked in another tight, one-run affair for much of Saturday afternoon’s game against the Pirates at PNC Park, but the home team rallied for four runs off reliever Craig Stammen in the eighth inning, sending San Diego to a 6-3 loss.

The Padres’ offense struggled again to find the big hit at the clutch time, though Manny Machado continued his surge at the plate with a homer and a ninth-inning, run-scoring single. And Chris Paddack’s return to the rotation was largely a sign of more good things to come.

Overall, the game turned on just a handful of moments, each of which is indicative of larger trends for the Padres. Here’s a breakdown of those situations.

Top of the fourth: Kiss it goodbye

Machado gave the Padres a 1-0 lead when he launched a pitch from Chris Archer to left-center for his second homer in as many days and his sixth dinger in nine games. The ball went a projected 432 feet, per Statcast, after being sent to left at 107 mph off the bat.

• Box score

After signing a 10-year, $300 million deal with the Padres this offseason -- the largest free-agent deal in the history of American sports at the time -- the expectations were understandably sky high for Machado. Through his first 66 games with his new club, Machado posted a near-league-average .725 OPS.

But over the past nine games, Machado has begun to show off his exceptional power, which helped him produce four straight seasons of 33 or more homers from 2015-18.

“He’s been crushing baseballs,” Padres manager Andy Green said. “That home run he hit today, he annihilated. The single up the middle was hit hard, too. He continues to do it over and over, and this is why we got him. We believe he can be that guy, that force in the middle of our order.”

Bottom of the fifth: Carried away

Paddack’s first start back from a rest-centered stint with Class A Advanced Lake Elsinore went well for the first four innings, but it ended on a frustrating note.

After Jacob Stallings singled with one out, Pirates manager Clint Hurdle sent Jose Osuna up to pinch-hit for Archer. Osuna had knocked in the go-ahead run in Friday’s 2-1 loss. On Saturday, Paddack threw him a first-pitch 93-mph fastball that was center cut, and Osuna lifted it high to right-center field, with it narrowly clearing the wall.

Paddack went to his knees in disbelief beside the mound as his lead evaporated on two pitches.

“Watching [Wil] Myers, watching [Josh] Naylor track that ball, I thought it was a popup,” Paddack said. “... Just frustrated. I know the ball carries to right, but personally, I thought that was staying in the park.”

Otherwise, Paddack was reassured by his outing. He went five innings, allowing just the two runs on five hits, and he said the changeup he worked on in his Minor League stint hit the zones he wanted it to, though the results didn’t show in whiffs, as Paddack recorded just one strikeout.

“They laid off a lot of good changeups in the bottom of the zone,” he said. “Changeups that I usually get [a] swing and miss or an aggressive take [on], they just completely spit on it. So [I] tip my cap to those guys. It’s a tough lineup.”

Top of the eighth: Bad bounce, tough outing

With the game knotted at 2, Stammen entered in relief for the Padres. Stammen has had two rough outings in June, allowing at least three runs in each, and Saturday became another tough one.

It was all set up by a bad bounce. Starling Marte led off the eighth with a long hit to right field, which took a sideways ricochet off the Clemente Wall and eluded Naylor in right field. That allowed Marte to stretch for third base, and instead of potentially having a leadoff man on first, the go-ahead run stood 90 feet from home.

“When the ball takes a weird hop off the right-field wall and turns into a triple, it changes the context of an inning,” Green said, “because you kind of have to gamble to keep them from scoring a run right there, which usually [either] gets you out of there with a zero or adds on two, three or four runs at that point in time.”

This time, it was the latter, as Stammen tied his season-high mark for runs allowed in an appearance (4). With the bases loaded after an unintentional walk and an intentional walk, Adam Frazier knocked a go-ahead two-run single to provide the winning margin. Elias Diaz and Jung Ho Kang each knocked in insurance runs.

“Craig’s pitched through those situations before, and just a couple of ground balls that went right through holes,” Green said. “He’s looking for a ground ball right there to get a double-play ball, [but] it just goes right up the middle. And that’s just part of it, when you walk the bases loaded and take a shot.”