I walked into the Dodgers’ team store the other day and asked whether I could buy any “Beat SD” merchandise. Of course not.

I walked into the San Diego Padres’ team store Monday. I did not have to ask whether I could buy any “Beat L.A.” merchandise.

The rack of “Beat L.A.” shirts stared me in the face as soon as I entered the store. There are no other words on the shirt: nothing about San Diego, or the Padres. It is a rallying cry at Petco Park, but it is also a civic mission statement.

The San Diego Padres are selling “Beat LA” T-shirts in their team store.

(Bill Shaikin / Los Angeles Times)

Above the rack of “Beat L.A.” shirts: more shirts, with this message: “SD > LA.”

Each shirt costs $49. On Tuesday, the Padres host the Dodgers in Game 3 of the National League Division Series. In the hours preceding the game, a team store staffer said, the shirts would sell briskly.

“Like grab-and-go,” she said.

The “Beat L.A.” chants will be heard all night long, and they will be deafening. But it is a testament to the uneven and underachieving history of the Padres that four people with ties to the team could not agree when “Beat L.A.” became a big deal.

“I think it’s more of a recent thing,” said Dodgers manager Dave Roberts, who was raised in San Diego County. “I don’t think that, when I was growing up watching Tony Gwynn, it was a thing.”

Said Tony Gwynn’s son, Padres broadcaster Tony Gwynn Jr.: “It was a thing, but we didn’t get a chance to use it very much during that time.”

Gwynn Jr. said he remembered the “Beat L.A.” chants when the Padres beat the Dodgers by one game for the 1996 NL West championship.

“Outside of that, it was really reserved for Lakers-Celtics, as far as I could tell,” he said.

“I think, at that point, the Padres had not established themselves enough for the fans to feel comfortable enough going that route. A lot of those times, it was my dad: People were coming to watch him do his thing against the Dodgers, who he had a lot of success against.”

Steve Garvey, a most valuable player for the Dodgers, said he recalled “Beat L.A.” chants when he played for the Padres from 1983-87. At the time, he said, the Dodgers were more of a national attraction like the New York Yankees, less of an actual competitive rival.

“For the Padres, it was always a way to stimulate the team and the fans to get engaged,” Garvey said. “Now, that stadium rocks. It’s as loud as any place.”

San Diego pitcher Joe Musgrove grew up going to Padres games in the 2000s.

“I was one of those kids chanting it back then,” Musgrove said. “I don’t think there was as much passion behind it back then as there is now, but it’s always been a rivalry.

“If you’re from San Diego, you should grow up not liking Dodger blue.”

A shirt on sale in the Padres’ team store ahead of the 2024 NLDS against the Dodgers.

(Bill Shaikin / Los Angeles Times)

The Padres sold a record 3.3 million tickets this year, en route to their third postseason appearance in five years. The team, born in 1969, never even sold 2.3 million until 1998, when the Padres made their third postseason appearance in their three decades.

“When I was a kid, and even past a kid — up until I got into pro ball, really — it had been all Dodgers, all the way,” Musgrove said. “They had beaten us down for years and years. It was a rivalry at one point, and then it got the point where it felt like San Diego was just kind of hanging onto something that wasn’t there.”

When the Padres eliminated the Atlanta Braves in the wild-card round last week and advanced to the NLDS against the Dodgers, the Petco Park scoreboard lit up with “BEAT LA” before all the Braves had retreated to their clubhouse.

Former Padres first baseman Eric Hosmer tweeted: “Padre fans, honest question. Did we not graduate the #BeatLA chants?”

The San Diego fans love the chants. Baseball is about the fans. The chant stays.

But Hosmer poses an interesting thought: When the Padres were terrible, beating L.A. could make their season. That should not be the case any more.

“I think he is onto something,” Gwynn Jr. said. “It doesn’t change the fact it has become more of a heated rivalry because the Padres have gotten better. But, in terms of the organization, that is always the goal, right? To win a World Series?

“If you want to be mentioned in the same breath as the Dodgers, the Phillies, the Yankees, you’ve actually got to win the title.”

Said Roberts: “That’s the whole thing. That’s what great about rivalries. Even in college football, if we beat Ohio State, or we beat Michigan, or we beat ‘SC or UCLA, that’s all that matters.

“That should not be all that matters, right? It should be about winning the most games. But it’s still kind of fun.”

Musgrove said there is a purpose behind those two words, and all the decibels that come with them.

“For the past couple years, the path to the World Series has run through those guys,” he said. “Until we can start taking the division, and running the show as far as the division is determined, we know that is a team we’re going to have to beat consistently.

“We’ve played them a lot better this year. We’ve played them tough this series. We’ve got a good chance to win this thing at home. So we’re excited.”

The Padres fans will be roaring Tuesday. The team will be giving out rally towels. In what struck me as something of an upset, the towels will not read “Beat L.A.”