SAN DIEGO -- Before Opening Day, the Padres insisted the 2019 season would mark the start of something different. This certainly qualifies:

San Diego hit the midpoint of its season Friday night, and did so by lining up for a pretty darn meaningful series against the Cardinals at Petco Park. Both teams are in the thick of the Wild Card race with clear playoff aspirations.

To say the least, it's been a while.

• Box score

The Padres held on for a tense 3-1 victory, riding back-to-back sixth-inning homers from Fernando Tatis Jr. Fernando Tatis Jr. and Eric Hosmer. As if to emphasize the importance of the series, closer Kirby Yates was called upon for a four-out save for the first time this year.

“This,” Yates said, “is when the season gets fun.”

When Yates punched out Paul Goldschmidt to end the game, the Padres officially hit the halfway mark at 41-40. They haven’t been above .500 through 81 games since 2010 -- the last time they made a legitimate push for the postseason.

“We like that we're in the thick of it,” said Padres manager Andy Green. “We've got some work to do to be a postseason club. But we like where we're trending right now, and the general vibe in the clubhouse is that we could do something special here.

“That's a stark contrast from the last couple of years.”

No kidding.

Still, as Green noted, there’s work to be done before the Padres are a bona fide “postseason club.” Here are the three things that need to happen:

1. Keep the OBP trending upward
Down the stretch, the power won’t be an issue. With bats like Hunter Renfroe, Franmil Reyes and Manny Machado, the Padres will almost certainly shatter their franchise home-run record this season.

But a far more meaningful trend has emerged this month. The San Diego offense ranks seventh in the Majors with a .338 OBP in June.

“Guys are synching in, figuring out who they are and how they can help the team,” said Padres hitting coach Johnny Washington. “Everybody knows where we need to be at the end of the year with getting on base. That’s something good teams do.”

And, frankly, the Padres haven’t been a good team for a while. They’re riding a streak of five straight seasons in which they finished last in the Majors in on-base percentage. Mercifully, that’s slated to end this season.

The improvement starts atop the lineup. Tatis returned from his hamstring injury in early June, and it’s no coincidence that his arrival coincided with the offense’s surge. He homered and walked on Friday, and he’s reaching at a .452 clip since his return.

“We’re doing something good over here,” Tatis said. “We just need to keep going.”

2. Bolster the starting rotation
There might not be a general manager with more Trade Deadline options than A.J. Preller. He’s got the best farm system in baseball, a handful of big league-ready trade options and legitimate cases to buy, to sell and to stand pat.

That said, the Padres don’t necessarily need to make a trade to upgrade their rotation.

On Friday night, Dinelson Lamet worked five innings for Triple-A El Paso, striking out seven in his sixth rehab start. Lamet missed all of 2018 because of Tommy John surgery. That came on the heels of a season in which he recorded the highest K/9 ratio of any starter in Padres history.

If Lamet can improve on that stellar rookie season, it would give San Diego a serious boost. The Friars took a huge risk when they entered the season with the youngest starting five in the Majors. They’d posted the highest rotation ERA in the National League in 2018.

So far, they’ve made it work. But after a strong start, the rotation owns a 5.81 ERA since the beginning of June. There’s room for improvement.

3. Solve the middle innings
There’s no obvious answer here. A season ago, the Padres dealt Brad Hand and Adam Cimber to Cleveland. Then, they moved Matt Strahm to the rotation this winter. In Spring Training, Jose Castillo suffered a flexor strain in his left elbow.

That’s an awful lot of missing pieces to overcome. What was once the team’s biggest strength is probably its most glaring weakness now. The bullpen ERA sits at 4.79 this season. It’s 5.56 since the start of May.

Yates has been arguably the best closer in baseball this season (and he set a franchise record by recording his 27th save before the All-Star break). But the Padres have struggled to find a bridge.

Trey Wingenter has been excellent at times. He’s also been erratic. Craig Stammen has been useful, but the Padres would prefer to use him less frequently and more as a middle-innings fireman. Castillo? Still hurt, with no timetable for a return.

In a muddled group of relievers, the Padres will look for answers everywhere. Luis Perdomo, who has a 0.49 ERA this month, worked a dominant seventh inning on Friday. Rookie starter Cal Quantrill, who moved to the ‘pen when Logan Allen arrived, worked two scoreless frames against the Cardinals.

“We threw up zeroes in five innings of bullpen work today,” Green said. “A lot of people like to say our bullpen’s not that great. It was great tonight. We did some really good things. We’ve got good pitchers down there.”

Maybe Perdomo fills the void. Maybe it’s Quantrill. Maybe it’s 20-year-old Andres Munoz, who is striking out 15 hitters per nine at the upper levels of the Minor Leagues, while also significantly lowering his walk rate.

But it needs to be someone. The Padres’ status as playoff contenders might depend on it.