The Houston Dynamo got a good result in the first leg of their Western Conference semifinal series with the Seattle Sounders. Based on their experience from last year, they know that coming home with that advantage won't guarantee them anything.

A testy series concludes Sunday at Robertson Stadium when the Dynamo and Sounders determine which club advances to the conference championship.

Houston was the two-time defending MLS Cup champion when it earned a 1-all draw at New York in the semifinals last year. The Dynamo's bid for a third straight title went awry in the return leg with a stunning 3-0 loss to the Red Bulls.

This year, Houston survived the hostile environment of the first-ever playoff game at Qwest Field for a scoreless draw in the first leg. The Dynamo hope to be better prepared to complete the job done at home this time.

"We did the same thing last year and we didn't win," Dynamo coach Dominic Kinnear said. "If you depend on playing and winning at home then you're looking at something that might not happen."

Houston got a positive result in the first leg, and also appears to have angered Seattle. The Sounders were critical of the referees as the Dynamo committed 18 fouls to six for Seattle.

"It's not rugby. It's still soccer," Seattle star Freddie Ljungberg said.

The defense-oriented style of play isn't a surprise. Both teams allowed the fewest goals in the league with 29 and know that scoring chances come at a premium.

"I think we just have to move the ball," Seattle forward Steve Zakuani said. "Against that kind of team, if you keep the ball too long they get on you, they get guys back and you lose it. They are physical, they're strong, but if the ball is moving they commit a lot of fouls. Move the ball, keep the game flowing and we should be fine."

There could be some bad blood lingering from an incident in the first leg in which Houston's Ricardo Clark kicked former Dynamo forward Nate Jaqua above his left eye, resulting in blood trickling down Jaqua's face.

"That's what I expect," Jaqua said of the Dynamo. "They've been good in the playoffs because they are physical."

Another former Dynamo player - Patrick Ianni - started in the first leg for the Sounders because defender Tyrone Marshall was ruled out with a sprained knee right before kickoff. It's unclear if Marshall will return.

"Even though we have complete confidence in Patrick Ianni, and Patrick played very well, still it's a last-minute change," Seattle coach Sigi Schmid said.

Houston went 8-1-6 at home, and is 4-1 at home all-time in the playoffs. The Dynamo announced they sold out the lower bowl for Sunday's match.

"I heard it's sold out, so it's going to be a great atmosphere," Seattle goalkeeper Kasey Keller said. "We are looking forward to going and disappointing a lot of people in Houston."