MIAMI -- Brian Anderson’s walk-off double nestled into the left-field corner at Marlins Park, capping Miami’s 4-3 victory on Thursday afternoon. As Anderson was mobbed at second base, nine Padres slumped their way toward the dugout -- and a disheartening 1-5 start to their second half.

It began with so much promise. The Padres hit the All-Star break at .500 with a young team and countless possibilities on the trade market. Now, the only thing standing between them and a winless week was Chris Paddack’s near no-hitter on Wednesday night. And even that almost slipped away.

“It just was not a good baseball series for us,” said Padres manager Andy Green. “We were not fundamentally sound. We didn’t deserve to win.”

• Box score

It culminated with right-hander Trey Wingenter hanging a slider that Anderson pulled down the line. For a team teetering on the fringe of National League Wild Card contention, the Padres now need a quick turnaround, or they’re probably destined to be sellers at the July 31 Trade Deadline. Here are five takeaways from a tough-to-swallow series finale in Miami:

1) Tatis is in his first career slump
It speaks volumes about Fernando Tatis Jr. that he launched a 418-foot home run, yet clearly is still in a funk. The rest of his performance this week in Miami was well below the lofty standards he has set for himself.

Tatis committed two throwing errors on Wednesday and another on Thursday. He went 1-for-13 this series with eight strikeouts.

“It’s a rhythm sport,” Green said. “Everything in baseball tends to come in bunches. … There’s a world of confidence he’s going to be completely fine. He’s walking through it mentally really, really well right now. He’s going to be fine. He just hasn’t been as crisp.”

2) The Padres might have solved the middle innings

The Padres spent the first half of their season with Andres Munoz in the Minors and Matt Strahm in the rotation. In the meantime, their middle relievers floundered and the bullpen’s ERA skyrocketed.

Munoz and Strahm might be the solution. The duo combined to work three scoreless innings with five strikeouts on Thursday after starter Dinelson Lamet faltered early.

Munoz, a 20-year-old rookie, was particularly impressive, striking out the side in the seventh after a 1-2-3 sixth. He even reached 102.3 mph with his fastball, eclipsing his own record for the fastest Padres pitch recorded by Statcast.

3) Lamet is still shaking the rust off

Even during his breakout 2017 season, Lamet often struggled with his command, and his 11 percent walk rate was far too high. So, yes, his command issues through three starts are troubling. But it’s also worth remembering that there’s rust to shake off after Lamet missed 15 months following Tommy John surgery.

“The more I’m on the mound, the better I feel,” Lamet said. “The more batters I face, the better I feel. As that continues to go, I’ll feel even better.”

On Thursday, Lamet allowed three runs (one earned) in four innings. He walked two and surrendered six hits. But he was also done in by some shoddy defense in the second inning, when Austin Hedges fielded a Caleb Smith bunt (which replays showed was probably foul) and fired the throw into center field.

4) Margot is playing his way into the long-term center-field picture
There’s probably no bigger long-term position of need for the Padres than center field. But maybe they have an in-house answer after all. Manuel Margot reached base all four times he came to the plate, and he ended up just a homer shy of the cycle. Since he took over the regular center-field job from Wil Myers on June 23, he’s hitting .283/.415/.623.

“I want to think about it in terms of maintaining it and working hard,” Margot said. “These are things that are fleeting and can go away at any time. So if I maintain that work and maintain that approach and things that I’ve been doing, I think I can be the offensive player that I am.”

Green even mused on the possibility that he might move Margot up in the order this weekend against the Cubs. Margot, who is still only 24, has played his way back into the club’s short-term plans. If he can perform like this consistently, he’s destined to find his way into the long-term plans, too.

5) Is this the streaky Padres’ last chance to bounce back?
It’s not the first time the Padres have put themselves in a precarious situation this year. On three different occasions they’ve dropped to .500 or below with a skid, only to reel off impressive winning streaks in the immediate aftermath.

But their response to these particular struggles might be season-defining. The Trade Deadline looms, and the team’s performance over the next week might dictate the strategy of general manager A.J. Preller.

The Padres -- currently four games below .500, tied for their lowest mark of the season -- have three games against the Cubs in Chicago before finishing their trip with three against the Mets in New York. It’s gut-check time.