WASHINGTON -- The Padres’ Trade Deadline strategy was always going to be colored partly by their results on a tricky nine-game road trip to open the second half.

So far, they’re playing like buyers.

After winning a tough series in Cleveland over the weekend, the Padres opened a three-game set in Washington with a 4-0 victory on Tuesday night at Nationals Park. Luis Arraez and Jurickson Profar hit back-to-back homers to get San Diego on the board in the fifth. That was enough for Randy Vásquez, who was equal parts dominant and efficient. He needed only 68 pitches to work six-plus scoreless innings.

“Exceptional outing for him, getting into the seventh,” said manager Mike Shildt. “Lower pitch count, but, man, he had more than done his job. He made a lot of quality pitches, lot of quick outs, threw up a lot of zeros.”

It completed quite a turn through the starting rotation for the Padres. Right now, it’s only a four-man group -- with off-days and the All-Star break affording them that luxury. Those four starters -- Matt Waldron, Dylan Cease and Michael King in Cleveland and Vásquez on Tuesday in D.C. -- each worked at least six innings while allowing one run or fewer.

The Padres still must figure out the fifth spot in their rotation, with varying degrees of uncertainty surrounding Joe Musgrove and Yu Darvish. But Vásquez’s emergence sure has stabilized things. In his last five starts, he’s posted a 1.71 ERA.

“I feel like I can fill one of those spots in the rotation,” Vásquez said through interpreter Pedro Gutierrez. “The results speak for themselves. It’s a role I’m willing to take on. I feel the responsibility toward my teammates, toward my team.

“It definitely hurts that teammates of mine are not available for us right now. But I definitely feel like I can help the team win.”

Lately, he’s done exactly that.

No doubt, it’s been an impressive run for the Padres rotation. But that’s unlikely to change the team’s desire to add at least one starter ahead of the July 30 Trade Deadline.

Musgrove is working his way back from right elbow inflammation and a bone spur, and he hasn’t been himself all season while pitching amid injuries. With Darvish, it’s unclear whether he’ll be back at any point this year, with his absence having been deemed only “indefinite.” The veteran right-hander was placed on the restricted list earlier this month to tend to what the team has called a personal family matter.

At present, there’s one place open in the rotation. But King has already surpassed his career high in innings as a professional, and Waldron is one inning away from doing so. Based on recent evidence, neither is showing signs of slowing. But just ask the 2021 Padres about the consequences of not adding to a thin rotation at the Deadline.

They’ve got one week to act. In addition to a starter, the Padres could also use a middle-innings bullpen arm and perhaps an outfield/bench bat.

At the break, it was worth wondering whether the Padres would buy at all. But lately, they’ve staked their claim in a crowded National League Wild Card race.

“We’re starting the second half in a very good way,” Arraez said. “We’re a good team.”

Of course, a strong road trip won’t suddenly force the Padres to push all of their chips into the middle. It’s still a seller’s market, and they’ve already parted with a number of their top trade assets to acquire Cease and Arraez. Besides, they’re not the only contender searching for pitching.

The Padres remain reluctant to part with any of their top four prospects -- Ethan Salas, Robby Snelling, Dylan Lesko and Leodalis De Vries. Realistically, that probably leaves them swimming in the shallow end at the Deadline. The trade market’s prize arms -- Garrett Crochet and Tarik Skubal -- are almost certainly out of San Diego’s price range, unless those top prospects are in play.

But there are other arms available, and the Padres will be active in their pursuit over the next seven days. In the meantime, Vásquez’s emergence gives them some measure of comfort with their in-house options.

“The confidence has been growing,” Shildt said of Vásquez. “He’s pitched really well and continues to improve.”

It can’t be overstated just how important Vásquez’s emergence has been -- and just how timely.

“I’ve felt good,” Vásquez said. “The everyday work -- it’s been showing.”