LOS ANGELES — The best rivalry in baseball arrived with warnings that went unheeded. The elements have been there for some time, but it took the first two games of the National League Division Series for everything to spill into the margins. The Los Angeles Dodgers, winners of 11 of the past 12 NL West championships, “the dragon up the freeway,” and the San Diego Padres, the plucky little brothers with a preponderance of talent (and a recent history of beating the Dodgers in the postseason), meeting in a five-game series with epically high stakes. The clash was inevitable.

It is, now, after 18 innings, a full-on spectacle. There have been a preposterous number of home runs, more than a few simmering feuds, borderline-criminal fan involvement, and a tied series heading to San Diego for Game 3 on Tuesday. The Padres’ Game 2 win on Sunday night in Dodger Stadium was a sprawling mess of a thing, a nine-inning opera filled with argument and innuendo and just the right amount of childish back and forth. There was more drama than a 10-2 game has any right to claim.

It started immediately, when Fernando Tatis Jr.’s first-inning homer landed in the Dodgers’ bullpen, and none of the relievers or staff members moved, or even acknowledged the existence of a baseball headed in their direction. In the bottom half of the inning, Jurickson Profar stole a homer from Mookie Betts (now 2-for-31 in his last three postseasons as a Dodger) when he went into the third row of the left-field stands near the foul pole and snared it out of a fan’s waiting glove. He proceeded to slake his thirst for the spotlight by backpedaling away from the stands long enough for Betts to get nearly three-quarters of the way through his home-run trot before turning toward the infield and throwing the ball back in.

“I had no idea he caught it,” Padres center fielder Jackson Merrill said. “When he threw it in, I thought, Oh my God — what are we doing? It’s the first inning, and it’s going like this? I love it. Regardless of what [Profar] does, we have his back. But if I was Mookie, I would have been pretty mad.”

Merrill owned a chapter unto himself. One inning he unleashed his Freddie Freeman-esque opposite-field swing for an RBI single, and the next he was leaping at the wall to take a double away from Kike Hernandez, and two innings later he was hitting an opposite-field, two-run homer, one of six the Padres hit in Game 2. He ended up with three hits and three RBIs.

“That kid definitely doesn’t look like he’s 21,” said Padres shortstop Xander Bogaerts, once a 21-year-old postseason phenom himself. “He’s a great kid, a credit to his family. He’s something special, and he’s been doing it all season.”

It all felt high-charged, if rather tame, until the igniting — or reigniting — factor in so many baseball feuds: the simple act of a pitched ball hitting a star player. Dodgers starter Jack Flaherty hit Tatis on the left thigh with a high-velocity sinker as Tatis led off the sixth inning. It would have been no big deal had Tatis not rounded the bases after his first-inning homer with an arthritic slowness, only to then double in the third. But he had, and so it was.

After the ball hit his leg, Tatis’ trek to first base was long and arduous, nearly epic. As it proceeded, Profar, who needles the opposition like it’s his job, came to the plate engaging in a spirited discussion with Dodgers catcher Will Smith, with whom he has a history of spirited discussion. Manny Machado, on deck at the time, let it be known that he felt the pitch was intentional.

Flaherty said he didn’t hit Tatis intentionally; that would have been stupid under the circumstances: the Dodgers down 3-1 with Profar, Machado and Merrill to follow. “I think their whole side thought I hit him on purpose, but it doesn’t make sense. Dude, I get how it looks … but that’s not the situation to hit someone,” Flaherty said. Machado, apparently unswayed, said, “Get him out. If you can’t get him out, don’t hit him.”

The sequence of events is mostly immaterial, except to say that it resulted in Flaherty, who runs a bit hot, and Machado — who, well, same — continuing to express their differences after Flaherty struck out Machado. While warming up before the bottom of the sixth, Machado threw a baseball into the Dodgers’ dugout, and threw it with enough force to catch the attention of both the umpires and the Dodgers’ dugout. Again, none of this represents the height of intellectual achievement, but it works as entertainment.

“Not going to get punked if he wants to do that,” Flaherty said. “Everybody just happened to catch me and him going at it. Everybody wants to look in and point fingers, like, “Oh, I started things.’

“It’s s—. Everybody catches the end of it.”

At roughly the same time, Profar was finishing his warmup throws in left field by tossing the ball to a fan, who lobbed it back onto the field in a way that suggested misguided playfulness and not violent intent. It did, however, spur two other fans to throw baseballs at Profar, who responded by flying into a justified rage. Padres manager Mike Shildt got nearly as enraged, beer cans and other forms of garbage were thrown at Tatis in right field, and the Padres were briefly taken off the field.

“Not ideal,” Machado said.

All of these sideshows are taking place in a series with a ridiculous amount of talent on the field, but clubhouses that couldn’t feel more diametrically opposed. The Dodgers are still relatively buttoned-up, old-school, image-conscious. They go about their business like it is actually business, while the Padres seem to be engaged in an entirely different pastime, launching themselves at the game like satellites, the perfect representation of baseball’s counterculture. They apparently all got together and came up with the wild idea of hitting for average and putting the ball in play. Five of them in the starting lineup hit at least .275 this season, and the result is an offense that prods and nags and never goes away.

“That’s this team, man,” Machado said. “We’ve fought all year, and it’s awesome.”

The Dodger Stadium crowd boos each of the big-name Padres, but they react to Machado in a way that defies reason. They boo him — an ex-Dodger — not just like he’s a great player on a rival team; they boo him like he did something awful to each of their families and sends them periodic notes to remind them.

Against the backdrop of the Dodgers’ latest win-or-else postseason, it’s hard to overstate the stakes at play here. The climate feels perfect for yet another early exit for the Dodgers, which would make it three first-round exits in a row, but at this point it would be hard to classify it as an upset. The contrast is enticing: The Padres free of history and expectation, the Dodgers the carriers of ancient burdens.

The fluctuations are wild. In the first inning of Game 1, Machado hit a two-run homer that cut through the hate like a comet. An inning later, Shohei Ohtani stayed on top of a 97 mph, armpit-high fastball from Dylan Cease and sent it over the right-field wall for a three-run homer. The entire place shook, the fourth deck momentarily rocking like a suspension bridge. It was as if the entire building understood that this one swing — and the one violent bat toss followed by the one primal scream — showed Ohtani and the rest of the world what he’d been missing in six playoff-free seasons with the Angels.

“His emotions are something you’ve seen grow over the year,” Dodgers reliever Alex Vesia said. “It’s just him becoming more and more himself.”

Ohtani, as expected, has been the object of an inordinate amount of attention. Every player on each team has been asked to explain the Ohtani experience in an untold number of ways, and Ohtani himself was asked, before Game 1, if he expected to be nervous for his first postseason experience. In a rare move, he eschewed the formalities of the translation process and answered, in English, “Nope.”

“That was hilarious,” Vesia said. “The way he said it, and the way he smirked, is his authentic self.”

There’s something almost folkloric about Ohtani’s bearing, the way his politeness hides the savage competitor. On the field before Game 2, he was going through his Tommy John rehab routine, throwing the ball more than 200 feet on a line, reminding everyone that he is not only a better hitter than the hitters but a better pitcher than the pitchers. “We talk about it around here every single day,” Dodgers reliever Evan Phillips said. “He does something every day that impresses us, and he does something every single day that surprises us.”

Before Game 2, Shildt, an earnest and literal sort, was asked a long and winding question that eventually settled on a requirement that Shildt place Ohtani “in context.” Shildt didn’t say it, but there is no context. That’s the entire deal with Ohtani, the big and ongoing takeaway, that he is creating his own context. It is his most comprehensive feat.

They’ll start it all up again in Game 3, with the roles reversed and the Petco Park crowd heckling Ohtani like the Dodger Stadium crowd heckles Machado, and each game tossing on layers of importance, the tension crackling like high-voltage wires. The subplots run off the page: Will Freddie Freeman, the hobbled Dodgers’ inspiration in their Game 1 win, be on the field after his ankle injury forced him out of Game 2? Do the Dodgers have even close to enough starting pitching to take them through five games? Will Profar burrow deeper under the Dodgers’ skin?

“It’s a beautiful thing to be playing postseason baseball,” Machado said.

The only shame is that it can’t go beyond five games. Maybe the idea of a laid-back Southern California playoff series never had a chance, but after 18 innings of this, it’s unimaginable. Now each slight — real or imagined — will be seen through the prism of each slight that came before.