Talk out of Chivas USA camp this week has Wednesday night's U.S. Open Cup semifinal showdown with defending champion Seattle as the biggest game in club history.

Well, OK. The argument can certainly be made: Win this, and the Goats are playing for their first trophy. But bigger than the Major League Soccer playoff games in 2006, 2007, 2008 and 2009? It's a matter of perspective.

“It’s the first semifinal that [the club has] ever been in,” says forward Justin Braun, who has scored 10 goals this season, including a pair in the 3-1 quarterfinal victory at Houston nearly two months ago. “This club hasn’t done too well in the past in this tournament, so I think it’s a big steppingstone for us.”

The Open Cup is America's oldest soccer competition, dating to 1914, and MLS clubs have dominated since the league's 1996 inception, winning every year but one. Chivas has not contributed much to that success: The Goats had won just once in six Open Cup games before this year's tournament, eliminated by lower-level sides four times, including amateurs Roma FC from Dallas in 2006.

Victories over second-tier Austin Aztex and at Houston set up a third Open Cup meeting with the Sounders, which beat Chivas in 2007 and 2008, when Seattle was playing in the second-tier USL First Division.

The game will be played at tiny Starfire Sports Complex in suburban Tukwila, Wash., where the Sounders are unbeaten in five games -- including a quarterfinal victory this year over the Galaxy, in which Nate Jaqua scored twice; he also netted Seattle's only goal in a round-of-16 victory on penalties over the Portland Timbers -- and will be playing in front of a sellout crowd.

And Seattle is playing its best soccer of the season, with just two competitive losses since July 4, both in CONCACAF Champions League group-stage matches.

“Seattle's definitely a quality team,” Braun said. “It's going to be a tough game for us. We've got to go in there and execute our game plan and keep being tight defensively.”

The Goats are coming off a 1-0 victory over D.C. United, their first win since the end of July, but they've dominated Seattle since its MLS debut last season. Chivas is 2-0-2 in the series and hasn't conceded a goal. The Sounders have beaten every other team in the league.

D.C. United, which won its second Open Cup two years ago, plays host to 2002 champion Columbus in the other semifinal Wednesday. If Chivas wins, it would play in the final at D.C. on Oct. 6 or at Home Depot Center against Columbus on Oct. 12. Seattle would be home for the final, Oct. 5 at Qwest Field, if it beats Chivas.

So, biggest game in Chivas history? If they win it, sure. If they don't, not so much.

“It's a very big game for us, but we've had some big games in the past,” captain Jonathan Bornstein said. “We have an opportunity to go into the final of the Open Cup, and that's something this club has never had the opportunity to do. Playing in the semifinals is big, and we need to make the most of it and come away with a win.”

Kickoff is at 7:30 p.m., and the game can be seen at the Sounders' Web site.