SAN DIEGO -- The Padres reached the halfway point of their season on Sunday afternoon with a come-from-behind 5-3 victory over Houston. Ahead of their first off-day in 17 days, it’s time to address what's gone largely unspoken as they’ve racked up seven straight victories:

For the first time in at least a decade, the Padres are contenders.

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Fernando Tatis Jr. stole the show on Sunday with an incredible running grab in the top of the eighth inning. Manny Machado stole it back with a go-ahead opposite-field bomb in the bottom of the frame. The Padres have their longest winning streak since 2013, and they’re 18-12 at the midway point, their best 30-game start to a season since ‘10.

“We’re changing the culture out here,” Tatis said. “We’re building something different. Everybody knows what we’re capable of, and the thing is: We’re working for it.”

That last part is key. The Padres have spoken of changing the culture for some time. This time, it feels like more than just words.

"We talk about team baseball," manager Jayce Tingler said. "Not only is this a big win, but the importance of so many guys contributing. ... It's not a two- or three-man show. We're not riding two or three guys. We've got a full body of men that are contributing."

A week after the Padres left Arizona having lost five straight, the tone was noticeably different on Sunday evening. That turnaround began Monday night, and Tatis played the role of firebrand.

His heedless swing at a 3-0 pitch up by seven runs became the first grand slam of the Padres’ MLB-record four-game slam streak. They’d add another on Saturday, making it five slams in six games -- another MLB first.

“It’s been great,” said Tatis, who went 2-for-3 with a walk to add to his eighth-inning defensive gem. “I think there was a little bit more energy to the boys. Everybody’s on the same train. We’re pushing every single day. We’re playing for one another. We’re just playing great baseball right now.”

The state of Texas bore the brunt of that. San Diego won four against the Rangers across two cities. Then the Astros arrived at Petco Park, having won eight straight. They were swept over three games -- and outscored, 22-8.

A week that began with controversy ended with seven straight Padres victories -- perhaps spurred on by that controversy.

“We didn’t pay attention to that,” Tatis said Sunday. “The team [had] great meetings in there, and we just decided to go out and just ball.”

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No one can ball quite like Tatis. But lately, Machado has offered a reminder that he’s an other-worldly talent, too. After a slow start to the season, his OPS has risen 171 points in the last six days.

Machado is hitting .257/.359/.531, and if this shortened 60-game slate had an All-Star Game, there’s a decent chance Machado would be right next to Tatis on the left side of the National League infield.

“He’s Manny being Manny right now,” Tatis said. “He’s always been that guy, and we were just waiting. Everybody knew it was just a matter of time for it to click. Now, there it is.”

Tatis opened the eighth inning with a leadoff single off Astros reliever Enoli Paredes, setting the stage for Machado, who arrived at the plate hitless for the day, despite having compiled five consecutive multihit games.

Paredes threw a 96 mph fastball above the belt. Machado wouldn’t let it beat him. He lined an opposite-field blast for his eighth home run of the season and his third in five games.

“Just trying to get a pitch you could drive and drive it in the gap,” Machado told Fox Sports San Diego. “I know anywhere I could square it up, with Tati’s speed, he’ll be able to score.”

“He’s got it dialed in at the plate,” Tingler said of Machado. “Every time he steps in the box, we feel the threat, we feel the battle. He’s a dangerous at-bat right now.”

Indeed, Machado is heating up. So is the Padres bullpen, which tossed 7 1/3 scoreless innings after starter Adrian Morejon was hit hard early. It was the third time this week the San Diego relief corps has been asked to cover at least six innings. Two other games went extra innings.

Talk about earning your off-day. The Padres will take a deep breath on Monday. Then, they’re set to begin the second half of this extraordinary season in something of an unfamiliar role: contenders.