HOUSTON—Naturally, the top two defensive teams in the MLS fought to a scoreless tie for 90 minutes with their seasons on the line.
Brian Ching broke the deadlock with what he called one of the greatest shots of his career.
Ching scored six minutes into overtime and the Houston Dynamo advanced to the Western Conference final for the third time in four years with a 1-0 win over the Seattle Sounders on Sunday.
The teams both allowed only 29 goals in the regular season, the lowest in MLS. They tied 0-0 in the first leg of their two-game semifinal on Oct. 29, setting up the winner-take-all match in Houston.
Houston defender Mike Chabala set up the winning shot with a high cross from the left. The ball deflected off midfielder Brian Mullan and right to Ching, who beat goalkeeper Kasey Keller with a shot to the top left corner.
"I just kind of turned and hit one of the best shots of my life," Ching said. "I was happy to see that go in."
The Dynamo advances to the single-game West final to face the winner of the Chivas USA-Los Angeles match later Sunday. Houston improved to 5-1 at home in the playoffs and 9-1-6 at home this season.
Houston won the MLS championships in 2006 and '07, and Ching said the team drew on that experience as Sunday's game wore on.
"We've put expectations on ourselves," said Ching, the franchise's all-time leader in playoff goals (6). "Every year, we're one of those teams that realistically feels like we're one of those teams that can win the MLS Cup. The proof is in our results."
The Sounders, an expansion team, wrapped up their inaugural season by losing to Houston for the first time in five games (2-1-2).
"We attributed ourselves really well, and the city was phenomenally behind us," Keller said. "Now we have to take the pill of not winning this time and we have to go out and spend the offseason thinking about how we're going to make it better."
Seattle defender James Riley earned a red card in the final minute of overtime after tripping Ricardo Clark. The teams exchanged words at midfield before referee Jorge Gonzalez got in the middle of the crowd.
Houston outshot Seattle 15-10.
Dominic Oduro had three of Houston's nine first-half shots, including a drive off the left post in the 23rd minute. The 24-year-old forward from Ghana caught up to a long pass from Stuart Holden in the 30th minute, but his shot crossed just in front of the goal.
"I don't think we panicked," Ching said. "We were just a little unlucky on a lot of opportunities in the first half."
Seattle's best chances in the first half came on counterattacks, before the Dynamo's defense could get set.
Fredy Montero ran past a Houston defender, but his close range shot went into the side of the net. Steve Zakuani sent a cross into the goal area in the 36th minute and Houston's Geoff Cameron nearly deflected it into the net for an own goal.
Pat Onstad made a diving stop on Montero's shot in the 57th minute, one of the few scoring chances for either team in the second half.
"We knocked on the door a few times," Keller said, "but we just couldn't sustain enough pressure."
The Dynamo were back in the same position as they were last season, hosting a decisive game in the West semifinals. They tied New York 1-1 in the first game last year, then lost 3-0 in Houston.