SEATTLE — Blood, noise and yellow cards outnumbered scoring chances as the expansion Seattle Sounders debuted in the MLS playoffs with a 0-0 draw against the Houston Dynamo on Thursday night in the first match of a home-and-home, aggregate-goals set.

Second-seeded Houston, seeking its third MLS title in four seasons, denied a frantic late flurry of corner kicks and set plays by Sounders star Freddie Ljungberg.

The playoff opener was yet another splashy event in the Sounders' smashing inaugural season.

Seattle, the third seed in the Western Conference, set attendance records while becoming the first expansion team in 11 years to reach the MLS postseason.

The crowd of 35,807 at Qwest Field was the largest crowd for a conference semifinal playoff match in MLS' 13-year history.

It was the fourth scoreless draw this season for each team.

The second match of the series is Nov. 8 at Houston, where the Dynamo are 4-1 in the playoffs. They also have the league's best home winning percentage over the last four seasons. The winner advances to the one-match conference championship.

Houston could use the 10-day break after playing four times in 12 days.

Most of the rowdy fans were standing, singing and chanting and waving signs such as "Welcome to Green Hell" throughout the chilly night.

Lead owner and Hollywood filmmaker Joe Roth attended, and minority team owner actor Drew Carey walked the perimeter of the field before the game wearing a huge smile, a white team cap and one of the green-and-blue team scarves that were everywhere in the stadium and atop freeway overpasses around the city

The two stingiest defenses during the regular season — 29 goals against each in 30 games — bulled through 60 minutes. There were only two prime scoring chances in that span. The first came from former Dynamo player Patrick Ianni, who started because Tyrone Marshall had a sprained knee. He headed a shot off the crossbar in the 43rd minute on long free kick by Ljungberg.

In the 58th minute, Houston All-Star midfielder Brad Davis had his shot from the top of the penalty area poked away with a right hand by diving goalkeeper Kasey Keller.

The chippiness started when Houston goalkeeper Pat Onstad bulled Fredy Montero, Seattle's top scorer, to the ground in front of the goal after a whistle in the 16th minute. Onstad received a yellow card, as did Montero for racing up off the turf and charging at his 41-year-old opponent.