HOUSTON - Put yourself in Sheanon Williams' shoes for a moment.

You've scratched and clawed your way onto an MLS club. Then that club, fueled greatly by your tireless efforts, makes the postseason in only its second season of existence.

Would you be satisfied? Could you honestly look back and say before the biggest game of your franchise's history that just being there, with all it took to accomplish, is enough to put your mind at ease?

If you said yes, take Williams' shoes off. They don't fit you.

While that might constitute a good season for many, for the Union's overworked, undercompensated (league-minum $42,000 this season) defender, just being in tonight's do-or-die conference semifinal against Houston (8:30 p.m., ESPN2) isn't enough.

Because while he might have to layer his sentiments with such niceties as "Houston is a really good team," and "We match up well with them," the underlying tone is simply:

We know we can beat these guys.

"I'd be lying if I said I didn't think we can go out there and get this result," Williams said during a media session at the team's hotel last night. "They are a team that is a lot like us, and they do a lot of things similar to us. They are organized and smart, but so are we, and I feel that if we stick to our game plan, we can make it rough on them."

Williams has been part of a back line that, for much of this season, has been one of MLS' finest. The Union has allowed only 18 goals on the road, the second-lowest in the league to Seattle (17). At the University of Houston's Robertson Stadium, where tonight's game will be played, the Union is 2-0 and has outscored the Dynamo, 6-4, all time in the regular season.

"[To beat them] is why we are here," Williams continued. "In the beginning of the season, we talked about what our goals were, and they were to make the playoffs. Now that we are here, it's tough to be satisfied. Deep down, just getting here was never good enough for us . . . we're here to make some noise, as well."

But while the Union defense will need to remain unyielding, expect manager Peter Nowak to throw numbers forward, much as he and the technical staff did in the second half of Sunday's 2-1 loss to Houston at PPL Park. Needing to score two goals more than Houston tonight to advance to the conference final against Sporting Kansas City, and one goal to tie the aggregate series, this one is shaping up to provide end-to-end excitement.

While Nowak remained mum on the subject, veteran midfielder/forward Veljko Paunovic very likely will rejoin the lineup. Paunovic has been out since injuring his right hamstring following the Union's playoff clincher against Toronto FC. Up top, Sebastien Le Toux and Danny Mwanga have reunited, and it's very possible, given all that is required to advance in the playoffs, Nowak and Co. will decide to start midfielders Roger Torres and/or Freddy Adu. Both normally are second-half spark plugs, but time is of the essence.

"We definitely plan [defensively] on limiting [Houston's] opportunities, but we need to push forward the way we have been doing and create chances," Williams said. "We do a very good job of doing that, but we have a harder time putting them away. We've had a couple really good days of practice, and that is something we have definitely talked about and worked on."

When the curtain rises tonight in the Lone Star State, you will find Williams again tirelessly working the right flank. It's just what he does. It's why he was brought here. But to this defender, it's worth a mention only if it coincides with a win.

"It's been a good ride, and I am happy with the opportunity I have been given," Williams said. "I was thinking back on it just this week that, just a few years ago, I was in Harrisburg, not really happy with where I was at, and now I am definitely at a point where, when this year ends, I can look back and be thankful, but I am not ready for it to end yet, and neither are my teammates."