SAN DIEGO — The Padres are going for it. Over the past three days, they’ve made that abundantly clear, trading nine of their prospects — including six of their top 12 — to fortify their big league roster.

And why are they going for it? Because of nights like this one.

Before a record crowd at Petco Park, San Diego rallied from an early five-run deficit for a dramatic 6-5 victory over the rival Dodgers in 10 innings on Tuesday night. Manny Machado and Jackson Merrill homered off closer Blake Treinen in the bottom of the ninth — Machado with his second of the game — before Donovan Solano won it in the 10th with a walk-off single down the left-field line.

“That,” Merrill would say afterward, “was a real baseball game.”

It capped a wild Deadline Day that saw the Padres add lefty relief ace Tanner Scott to an already-excellent bullpen — a bullpen that pitched six scoreless innings after starter Matt Waldron had surrendered five runs (all in the top of the first).

The Padres did not use newly acquired righty Jason Adam, and they’re still waiting on three new pitchers to arrive — Scott, right-hander Bryan Hoeing and veteran lefty Martín Pérez. But in a way, Tuesday’s victory was set up by those acquisitions. Manager Mike Shildt could maneuver aggressively, using Jeremiah Estrada and Adrian Morejon with his team trailing by two runs late.

“That’s what you can do with deep bullpens,” Shildt said.

• Padres add RHP Jason Adam, trade 3 prospects to Rays

Added Merrill: “Our bullpen dominated tonight — then you add two, three more pieces? That’s pretty fun.”

Don’t look now, but San Diego’s deficit in the NL West is down to 5 1/2 games. Dodgers manager Dave Roberts — who was left empty-handed while trying to make a pitching change in the 10th inning — seems to think the race is on.

“Absolutely,” he said. “It’s 5 1/2 now. They made some additions, they’re feeling good, they’re playing great baseball. Probably, the month of July, they’ve played as good of baseball as anybody in all of the Major Leagues. They’re certainly feeling good about themselves, absolutely. We’ve got [Dylan] Cease tomorrow, so we’ve got our hands full again.”

Padres closer Robert Suarez worked a clean top of the 10th inning, setting the stage for Solano’s heroics in the bottom half. But that only came after a miscue from Roberts and the Dodgers’ coaching staff.

Shildt had called for Solano to pinch-hit for Jake Cronenworth, prompting a mound visit from Dodgers pitching coach Mark Prior. Immediately afterward, Roberts attempted to make a pitching change — which isn’t permitted following a mound visit.

The Padres had the matchup they wanted — lefty Alex Vesia facing Solano, who was also awarded a ball for the Dodgers’ delay. Solano fell behind, 1-2, before lacing the game’s decisive hit down the left-field line. The announced crowd of 47,559 — the largest in Petco Park’s history — whipped into a frenzy, the remarkable comeback complete.

“This is what fun teams, highly competitive teams, teams with a lot of hunger do,” Shildt said. “Regardless, they just compete.”

Shildt’s decision to pinch-hit for Cronenworth was at least somewhat unusual. Cronenworth has struggled against left-handers, sure. But he’s the team’s No. 3 hitter — and he did author one of the biggest hits in Padres history against this particularly lefty.

Nonetheless, the matchup called for Solano — a contact-oriented right-handed hitter who is excellent situationally. Cronenworth retreated to the dugout, where he stood next to his manager to watch the at-bat. Then, he was one of the first to greet Solano on the infield dirt after the walk-off.

“I was totally ready for the at-bat,” Cronenworth said. “But I mean, listen, I’m not mad about it. I completely understand it. I’m here to win.”

More than anything, Solano’s pinch-hit at-bat was a representation of the strength of this roster — because a hitter like Solano was available off the bench in the first place. The Padres are still waiting on the return of Fernando Tatis Jr. in right field. But otherwise, their offense is mostly complete.

As such, general manager A.J. Preller could push most of his chips toward acquiring pitching ahead of Tuesday’s Deadline. And after a 7-2 road trip through Cleveland, Washington and Baltimore, there was little doubt he’d act.

“What we’ve done over the past few weeks — and especially after the All-Star break — is put ourselves in a position to let A.J. do what he does,” Cronenworth said. “And he got guys that are going to come in here and really help us.”