Houston, which has won the MLS Cup in 2006 and '07, entered the postseason with a 4-0-2 record in its final six games.
They Dynamo extended it to seven straight without a loss as Andre Hainault and Calen Carr scored in the first half to lead Houston to a 2-1 victory over the Philadelphia Union on Sunday night in the first leg of the Eastern Conference semifinals.
It was the Dynamo's first victory in five tries against the second-year Union.
"We came here for a reason," Houston coach Dominic Kinnear said. "The main thing is the result. Our locker room is a good place right now."
Carr's goal in the 30th minute snapped a 1-1 tie and gave the Dynamo the edge in this series heading to Thursday night's matchup in Houston. The two-game series is based on aggregate goals between the two teams.
Sebastien Le Toux, who led Philadelphia with 11 goals in the regular season, scored the tying goal in the seventh minute.
"We have won there before, so we go back with the mindset that we can do it again," said Le Toux, a Most Valuable Player contender. "We have to regroup and we will do that."
Hainault gave the No. 2-seeded Dynamo a 1-0 lead in the fifth minute on a header. Brad Davis, who led the league with 16 assists, set up the score with a crisp pass into the box.
"Overall, I think we battled, knew what was coming," Dynamo midfielder Brad Davis said. "It was a typical road game, a typical playoff game and I think the guys grinded it out."
The game began with a sellout crowd of 18,539 fans waving rally towels. Before the game, Phillies shortstop Jimmy Rollins and Scott Hartnell and James van Riemsdyk of the Flyers were named as honorary captains.
Houston quickly seized the momentum and wound up with a big road victory.
"I knew that we would play well," Kinnear said. "To get a win against a tough team in a tough environment is pretty positive for us."
The Union had dropped only one game at home all season in a 2-1 loss to the Colorado Rapids on July 29.
Even though they led 10-5 in shots on goal and 7-4 in corner kicks, it wasn't enough.
"We had a lot of chances," Union manager Peter Nowak said. "It was a good number. The last piece is to finish them."
Houston was able to withstand a final flurry by the Union in the last 10 minutes, including a header by Jack McInerney in stoppage time which was stopped by Houston goalkeeper Tally Hall.
Hall had nine saves.
"I thought our attitude on the ball and our movement off the back was very good," Kinnear said.
While the Dynamo will be aiming to take another step towards a third MLS Cup title, the Union will be trying to do everything they can to extend their season.
"Our backs are against the wall," Union defender Danny Califf said. "We've played our best soccer when our backs have been against the wall."
(Copyright 2011 Philadelphia Union. Reprinted by permission)