Kansas City, Kan. ? The first time Houston came into Livestrong Sporting Park, the Dynamo went home on the short end of a 3-0 rout.

They haven’t lost since that Sept. 10 defeat — and this time, they left with the faint scent of champagne still clinging to their scraggly playoff beards.

“Three months ago, a lot of people just kind of have — I wouldn’t say cast us aside, but didn’t take us seriously,” coach Dominic Kinnear said after Houston reached the MLS Cup final by beating Sporting Kansas City, 2-0, on Sunday in the Eastern Conference title game.

“This is definitely a big statement to everyone who did that, that things can happen when things go well for you.”

The win also puts the Dynamo in the CONCACAF Champions League for the 2012-13 season. Houston last qualified for the competition in 2009-10.

Sporting, which won over legions of new fans by rebounding from an 0-6-1 start to finish atop the East in the regular season, has not made the title game since finishing as the runner-up in 2004. Sunday’s loss came in front of a standing-room-only crowd of almost 21,000, the biggest to pack into the team’s new stadium.

“We’re disappointed because we did realize that it could have been something special with the crowd, with us being at home and only having a one-game series,” defender Matt Besler said. “So that’s the unfortunate part about it.”

Andre Hainault and Carlo Costly scored second-half goals for Houston, which extended its unbeaten streak to nine — but now heads into the Nov. 20 title game, its first since the back-to-back championship seasons of 2006 and 2007, with questions about whether its star playmaker will be able to play.

Midfielder Brad Davis, who led MLS with 16 assists this season, went down with an injured right quadriceps while challenging Graham Zusi for a ball in the 37th minute.

“The prognosis is most likely not, right now,” Davis said of his chances at playing in the final against either Real Salt Lake or the Los Angeles Galaxy. “They think I have a torn quad. It’s just a freak thing; I was trying to turn and make a play on the ball. They didn’t hit me. They didn’t kick me.”

His emergency replacement, little-used Jamaican defender Jermaine Taylor, helped set up Hainault’s 53rd-minute goal for a 1-0 lead.

Kansas City keeper Jimmy Nielsen was able to get a glove on Taylor’s header off Adam Moffat’s free kick, but Hainault was there to tap the rebound into an open goal.

“Give a lot of credit to Jermaine Taylor,” said Hainault, who has two goals in the postseason. “He did well to get to that back post and get it across. I knew set pieces were going to be huge tonight, and they were.”

Costly’s goal came in the 87th minute, with Sporting pushed forward in search of an equalizer.