Before joining the Galaxy two years ago, Christian Ramírez spent two seasons with the Columbus Crew, winning an MLS Cup one year and then failing to get out of the first round of the playoffs the next.

The lesson, Ramírez said, is it’s far easier to climb to the top of the league than it is to stay there. And if the Galaxy, who won the MLS Cup last season, didn’t know that already they certainly found out Sunday when they opened defense of their title with a listless, lifeless 2-0 loss to San Diego FC.

The loss was the team’s first at Dignity Health Sports Park in 22 games and made the Galaxy the first reigning MLS champion to lose their season opener to an expansion team. The Galaxy may have sneaked up on teams last year, but this season they’ll be playing with a big target on their backs.

Read more: Galaxy lose in season-opening stunner to San Diego FC: ‘There’s no excuse’

“It becomes a championship game for teams to prove themselves against us,” Ramírez said. “It’s a little bit of the curse of the championship.”

And the MLS Cup Curse is real.

No MLS team has won back-to-back titles since Bruce Arena’s Galaxy in 2011-12. Since then, only two teams — the Seattle Sounders and LAFC — have even made consecutive appearances in the final.

More typical is the experience of Toronto FC, which won the Cup in 2017 then missed the playoffs the next season, losing 18 games, then the second-most in franchise history. Or Columbus, which won the Cup in 2020, then missed the playoffs the next year.

Ramírez, along with defender Eriq Zavaleta (Toronto, 2017) and goalkeeper John McCarthy (LAFC, 2022), are the only players on the Galaxy roster who have lived the curse. So it’s up to them, Ramírez said, to teach the lesson.

“It’s something that I’ll be able to pass [on], knowing what is coming, how teams get up for these games,” he said.

That would be a more valuable contribution than the one Ramírez made on the field Sunday. The replacement for striker Dejan Joveljic, who was traded to Sporting Kansas City after scoring the winning goal in the MLS Cup final, Ramírez was invisible against San Diego, taking just 12 touches and failing to get off a shot in 63 minutes.

But he wasn’t the only one who underwhelmed. Midfielders Marco Reus and Lucas Sanabria, playing in place of the Riqui Puig, out indefinitely with a torn ACL, and Mark Delgado, who was traded, were also ineffective. Without Puig and winger Joseph Paintsil, missing with a quadriceps injury, Gabriel Pec was the only designated player on the field, leaving the Galaxy’s so-called Killers Ps to be replaced by what coach Greg Vanney called the Deadly Ds; an attack that was disconnected, disjointed and not very dynamic.

“We didn’t look like a team that just won the championship,” the coach said. “We looked like a team that was fitting some things together.”

Which it is. A big reason for the MLS Cup Curse is the league’s complicated, merciless and convoluted salary structure, which punishes success by making it tough to squeeze the performance bonuses and the raises that come with a championship under a frugal budget cap. That’s why five starters from last season are no longer on the Galaxy roster and a sixth, defender Maya Yoshida, who led MLS in minutes played while captaining the Galaxy to the title, had to take a pay cut to come back.

That’s also why four of the players who appeared in Sunday’s opener weren’t even on the team for December’s MLS Cup final. If that wasn’t an excuse for the Galaxy’s listless performance, it was at least at explanation.

Yoshida, however, was having none of that.

Read more: Galaxy and LAFC are paying a price for success. Are they still MLS Cup contenders?

“There’s no excuse,” he said. “It’s a new season. Everybody started equal. We have to fight as a challenger.”

Especially when they’re the champions. Because while the Galaxy celebrated its title by unfurling a championship banner before Sunday’s game, afterward San Diego celebrated as if it had just won a final by beating the champs.

Yoshida said the team will either have to get used to that or find a way to stop it. And the time for that is short. The Galaxy play Sunday in Vancouver before opening CONCACAF Champions Cup play three days later, beginning a rush of seven games in at least two countries and three states in 27 days.

They’ll enter each one of those games with a big target on their backs.

“This is a new challenge for us, how [much] they want to beat us,” Yoshida said. “We have to be ready for this. We have to fight. We have to be better.”

Because as Christian Ramírez can attest, the MLS Cup Curse is real.

⚽ You have read the latest installment of On Soccer with Kevin Baxter. The weekly column takes you behind the scenes and shines a spotlight on unique stories. Listen to Baxter on this week’s episode of the “Corner of the Galaxy” podcast.

This story originally appeared in Los Angeles Times.