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).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.But for me DC United will win here.