FIRST LEG: Before the first leg of the Western Conference Finals between the Seattle Sounders and the L.A. Galaxy, the key battle between the two teams seemed obvious: the Sounders’ defense against the Galaxy’s offense. Going into last Sunday’s game, Seattle had surrendered only three goals in their last nine games, while the Galaxy had scored 12 in their last eight. The Galaxy were coming off a dominating 3-1 victory over San Jose in the second leg of the Western Conference semis. Meanwhile, the Sounders ground out a 1-0 win over Real Salt Lake on Thursday, with the series winner coming on this perfect volley from Honduran Mario Martinez.

A day before the first leg, Landon Donovan even complimented Seattle’s defensive strength.

“The first thing that stands out about them is defensively they’re very, very good,” he said. “They have continuity. I think Jeff Parke has been one of the best defenders in the league this year. Hurtado is solid. Johansson’s been good. The key to their team in any circumstance is (Osvaldo) Alonso.”

The battle everyone expected played out on Sunday night, and there was a clear victor: The Galaxy put up three goals on a Sounders defense that looked worn-out and unable to deal with the speed and combination play of the Galaxy’s attackers. Now, heading into the second leg next Sunday, which will air on ESPN at 9pm EST, it looks like the Galaxy are well on their way to returning to the MLS Cup.

When it comes to the ASN 100, Los Angeles dominates with six players in forwards Landon Donovan and Edson Buddle, midfielder Mike Magee, and defenders Todd Dunivant, Sean Franklin, and Omar Gonzalez. On the other side of the ball, Seattle features midfielder Brad Evans and forward Eddie Johnson, whose quality play with Seattle this summer earned him a call-up to the U.S. National team for its final two World Cup Qualifiers in October.

HISTORY: This season, Seattle won two of the three meetings between the teams, including a 4-0 victory over L.A. in August in front of nearly 61,000 fans at Century Link field. The Galaxy won the third match between the two teams 1-0 at the Home Depot Center, the last regular season game for each team.

The most compelling history between these two teams may not be what’s happened on the field but what goes on off it, in the stands. Los Angeles has big-name players in Donovan, Keane, and David Beckham, and a high-profile coach in Bruce Arena, but Seattle has developed overwhelming grassroots support in its six years in the league. The team’s average attendance for home games this year was 43,000, highlighted by the crowd of 61,000 for the Galaxy game and 66,000 for a match against Portland in October.

David Beckham, for one, said he loves the environment in Seattle.

“I’ve always been a big fan of Seattle as a franchise. The fans are incredible. Last time we played there…the atmosphere was the best that I’ve ever seen in this country. It’s like a European atmosphere. I love playing in atmospheres like that. It’s what I’ve done throughout my career. I love playing in opposing stadiums where they’re all on your back, and it’s nice to try and keep ‘em quiet.”

He’ll likely love it even more now that L.A. will kick off the game with a 3-0 lead in goals.

MATCHUPS: Heading into Sunday’s game, Seattle’s job was to try to shut down Keane, Donovan, and Magee. Those three players have proven to be L.A.’s most dangerous offensive threats throughout the playoffs; they’re the only players who have scored for the Galaxy. For L.A., Juninho needs to stifle Evans in midfield, and Omar Gonzalez and Tommy Meyer must deny service to and close space around Fredy Montero, and, if he’s healthy and plays, Eddie Johnson.

On Sunday, the Galaxy won all those key matchups. Magee and Keane scored their goals, Donovan got an assist and created numerous chances, and Montero and Johnson (who came in for Montero as a second half sub) barely saw the ball.

On Sunday, Seattle will of course need to push forward with abandon, but don’t expect Los Angeles to sit in a defensive shell. In fact, they don’t really have the personnel to do that. So many of their players are offensive-minded that the team will likely come out trying to score a couple early goals and put the series out of reach.

TACTICS: Over the past three games, the Galaxy have been playing a 4-4-2, with Gonzalez playing center back alongside rookie season-saver Meyer, who’s in for the injured A.J. DeLaGarza. Franklin plays right back, Dunivant left back, and they usually start Magee, Beckham and Juninho in midfield. Keane always plays up top, paired with either Donovan or Buddle.

In the first game of the series, the Sounders played a modified 4-4-2, with Christian Tiffert sitting just behind Fredy Montero. But if Eddie Johnson starts on Sunday, he will likely be up top alongside the Columbian striker. Parke and Jhon Kennedy Hurtado anchor the center of Seattle’s defense, and Alonso plays in front of them, a classic defensive midfielder. Evans and Mario Martinez are the other key figures in midfield, with Evans usually playing centrally and Martinez out wide.

Then again, given the offensive burden the Sounders bear heading into Sunday’s game and the goal advantage the Galaxy have, each team might come out with a totally different lineup. What do you think? Pick your Starting XI for Seattle and LA.

PREDICTION: Predicting this one’s pretty easy after Los Angeles posted the 3-0 win on Sunday. But I was planning to pick them anyway. The Galaxy have peaked, and their veterans look too determined to win to let any team stop them on their path to an MLS Cup repeat.

I spoke with Alexi Lalas on Saturday before the game, and he said, “I think there’s a confidence and a lack of fear that permeates that team.” When they stepped on the field against San Jose last Wednesday, said Lalas, “There was absolutely no fear that they were coming up against a team that they would struggle with.”

Look for L.A. to win the series in Seattle with a 2-2 tie or 3-2 win. If Houston can hold off D.C., the Dynamo will meet the Galaxy in Los Angeles on December 1st. That would be a rematch of the 2011 MLS Cup—one that all MLS fans should love to see.

READER FEEDBACK: We’ve told you what we think. What are your thoughts? Will the Galaxy hold their lead and find themselves in their fourth MLS Cup in three years? Or do Seattle have an epic comeback in them?

Andrew Lewellen (@AndyHLew), a former college soccer player and youth coach, is now a freelance writer based in Los Angeles. Read more of his soccer writing on his blog, Andy’s Pitch.