ST. LOUIS -- The Padres just seem immune to the Dog Days.

They traveled across two time zones after an emotional walk-off win on Sunday. Then, on Monday, they called up a new starting pitcher for a game played in 92-degree heat before a relatively sparse St. Louis crowd.

And it was never a problem. San Diego led wire to wire in a 7-4 victory over the Cardinals in manager Mike Shildt’s return to Busch Stadium. Manny Machado hit a two-run homer in the first inning and reached base three times. Jackson Merrill drove in three runs as well.

"We have fun every day, and we all love each other,” said Merrill, whose walk-off homer on Sunday capped a dramatic victory over the Mets. “The Dog Days aren’t even in our mind. There are obviously times we’re tired, because it’s baseball, and it’s a long year. But when you have fun, you don’t really think about your body. You just come to the field and compete.”

Monday afforded the Padres a rare opportunity to do so, knowing that a victory would gain them ground in the National League West. Both of their primary rivals in the division race had the night off.

Given the nature of the sport’s hottest division, opportunities like this are few and far between. The Padres took full advantage. With the victory, San Diego moved a game behind the D-backs for the top Wild Card spot in the NL and four games back of the first-place Dodgers in the West.

“We normalize every day being important,” said Shildt, who spent parts of four seasons as Cardinals manager before he was let go after the 2021 season. “We’re just going to take care of our business today and go take advantage of the opportunities that are out there.”

San Diego continues to show no signs of letting up, even amid a grueling stretch with 18 games in 18 days. There was no letdown in sight in a potential trap game on Monday.

The Padres simply did what they’ve done throughout the second half. They mashed. They played small ball. They pitched. They defended. They ran the bases. At the end, they had yet another complete team victory. It’s becoming a habit.

“Regardless of hot, cold, day, night, road, home -- they come to play,” Shildt said. “It’s a special trait.”

The Padres handed the ball to right-hander Randy Vásquez, who was promoted from Triple-A El Paso to take Matt Waldron’s spot at the back of the rotation. Vásquez was mostly sharp, working six innings of two-run ball.

If all of the San Diego starters were healthy and available, Vásquez is probably the sixth or seventh option. But it’s worth reiterating: Throughout a long season, those guys can be pretty important.

“Whenever I’m needed, I’ve just been ready to pitch,” said Vásquez, through interpreter Pedro Gutierrez. “The opportunity is arising, and I’ve been able to contribute.”

Indeed, in three starts this month, Vásquez has posted a 3.24 ERA. Monday’s effort was of particular importance, given that the Padres had taxed their bullpen in a big way chasing Sunday’s come-from-behind win.

“Randy has been the man all year,” Merrill said. “He’s pitched his [tail] off. He’s competed. … He’s been a dog out there, and it’s been really helpful to us. We’ve had some injuries, had some bullpen lag -- just using the bullpen a lot. For Randy to come in and just do what he does and have fun doing it, it’s awesome to see. It’s huge for us.”

Vásquez pitched with a lead the entire night, courtesy of Machado’s two-run blast. It was Machado’s 159th as a Padre, moving him four shy of Nate Colbert for the franchise record.

In the bottom of the frame, Machado likely saved a run, making a nice pick and a one-hop throw to beat Nolan Arenado by a step -- one elite defensive third baseman making light work of another.

“He took some really good at-bats,” Shildt said of Machado. “A big swing in the first to get us on the board, a nice play defensively. He just played a very, very good baseball game.”

Two innings later, Merrill extended the lead with an opposite-field, two-run single with two outs and the bases loaded. The Padres poured on three more runs in the fifth, putting the game out of reach.

“Everybody,” said Merrill, “is doing their part.”