WASHINGTON -- When a team finds itself in a win-or-else situation, facing off against a league's defending champion and current first-place squad is far from ideal. Doing so in the midst of a three-game losing streak, absent the services of five important players, makes for a particularly discouraging situation.Yet that's just where D.C. United find themselves this weekend as the Columbus Crew visit RFK Stadium for a match that will determine whether United's postseason hopes live or die. The Black-and-Red need to beat the league-leading Crew, win at Kansas City next Saturday and hope that other playoff-chasers like New England and Real Salt Lake slip up if they are to sneak into the final stages of the hunt for MLS Cup -- and they'll have to do it without Ben Olsen and Chris Pontius (both suspended), as well as Santino Quaranta, Bryan Namoff and Josh Wicks (all injured)."We really don't have any other way to go," said midfielder Clyde Simms. "We've known all season that we have the talent, but I feel like a lot of games we beat ourselves. So I think the biggest thing is just finding it within ourselves to turn it around."Once lost, momentum is no easy quantity to recapture and United's stunning three-game skid at RFK -- after going undefeated there for the first 11 league matches of 2009 -- has left them in need of an immediate jump-start. The venerable concrete bowl still rocks and rolls on game nights, but several D.C. players have lamented the increasing confident mentality shown by visiting sides."It seems like everybody comes in and has figured out how to beat us now," said Santino Quaranta last week. "It never used to be that way -- teams used to sit in at RFK and let us do what we wanted and keep the ball. They're coming in and beating us like men, basically, just really coming at us at our place. Whatever that is, it's not good."Precisely how Columbus will approach Saturday's tussle remains to be seen. The Crew have already locked up home-field advantage for the playoffs, but have yet to secure possession of a second consecutive Supporters' Shield trophy and will likely need a few more points to ensure themselves of that honor. Like United, they also hit the road for a pivotal CONCACAF Champions League group match at midweek, with Columbus traveling to Puerto Rico and D.C. heading to Mexico for a date with Toluca.The Crew have been consistently effective under both Sigi Schmid and Robert Warzycha over the past two years and United coach Tom Soehn believes his counterpart might make changes to his first XI, but not their shape and mentality."One thing you can expect is that their formation will stay the same and their tactics will stay the same. They defend with a block of eight and leave whichever two up pretty high, looking to counterattack, especially on the road," said Soehn. "The question you have is, who's going to play, because he's mixed it up pretty well, especially with guys being away with national teams."Playmaker Guillermo Barros Schelotto is Columbus' leading creative presence but the team has also proved its ability to garner results without the veteran Argentinean as home-grown youngsters like Robbie Rogers, Eddie Gaven and Matt Lenhart have stepped up at various important junctures this season.Yet United, who entered this campaign with such high expectations, are far more concerned with their own showing as they gird for the first of three make-or-break matches in an eight-day span."Each game now could be the last game, meaning-wise. If we want to make the playoffs we've got to win two games," said Soehn. "I think there's some urgency there, and probably some anxiety, but everybody knows what's at stake."