For the Galaxy, it’s win or go home

Major League Soccer’s new playoff formula really isn’t that complicated. So put away the slide rules and the calculators and all the confusing scenarios and focus on the one interminable truth that hasn’t changed since the Christians and Lions met in the first sudden-death match more than two centuries ago.

“Our goal is to go out and win the game. We do that, you can keep all your math and all the other theories,” Coach Bruce Arena said of the Galaxy’s Western Conference semifinal with Real Salt Lake on Sunday at StubHub Center (4:30 p.m., ESPN2, ESPN Deportes).

And if they don’t do that? Well, then things get complicated.

The winner of the two-leg playoff is determined by aggregate goals and since the first game ended scoreless, the teams are even heading into Sunday’s rematch. But MLS tweaked its postseason format this year, making away goals the first tiebreaker should a two-game series end in a tie. That gives Real Salt Lake an advantage since all it must do is play to a tie to advance.

As a result, the Galaxy isn’t thinking about ties.

“At the end of the day, if you win the game it doesn’t matter,” Landon Donovan said. “We don’t go into any game thinking we’re going to tie. We go into games thinking we’re going to win.

“Could it come down to [a tiebreaker]? Yeah, it could. But our focus is on trying to win the game.”

Scoring a goal would be a big help, of course. And in the last month the Galaxy hasn’t been very good at that.

In its last four games, the Galaxy has scored only three times, getting shut out twice and going the last 220 minutes without a goal. In its last three games, it has managed only six shots on goal and its big three — Donovan, Robbie Keane and Gyasi Zardes, who combined for 45 goals in the regular season — have only two since Sept. 28.

And that’s not the end of the bad numbers for the slumping Galaxy since its four-game winless streak is the club’s longest since May. Real Salt Lake, which knocked the Galaxy out of the postseason last November, has given up only one goal to an MLS opponent in 462 minutes, notching shutouts in its last four games.

“When our backs are against the wall we usually come up good. We’ll be in one of those situations again on Sunday,” said Keane, whose sore left hamstring is better but still not 100%. “We know exactly what we have to do. We have to make sure we don’t concede. And score goals.”

There’s also this: Since a season-opening loss to Real Salt Lake, the Galaxy has 15 victories and four draws in 19 games at StubHub Center, where it has averaged more than 2 1/2 goals per game.

Additional motivation could come from the fact the Galaxy isn’t playing only to extend its postseason run. It’s also playing to extend Donovan’s record-setting career, which will end in retirement when the team’s season does.

“I’m just going to play aggressively and, as cheesy as it sounds, play like it is my last game. If I do, it won’t be,” Donovan said.