Unlike the two-leg quarterfinals, the MLS semifinals will be decided in one game.

D.C. UNITED vs. NEW ENGLAND
Sunday, 4 pm ET, ESPN2 (live)
The New England Revolution, last season's runner-up to Los Angeles (which didn't reach the playoffs this season) stands in D.C. United's path to a fifth MLS title. D.C. United was the league's outstanding team for most of the regular season but slumped in the late going and needed Christian Gomez's heroics to take it past the New York Red Bulls in the quarterfinals. The Revs came back from a two-goal aggregate deficit to defeat Chicago despite the absence of defensive midfielder Shalrie Joseph (suspended) and attacker Clint Dempsey (injured). Joseph returns against United but Dempsey is listed as doubtful. ''They are pretty dangerous,'' United coach Peter Nowak told the Washington Post. ''Their combativeness, their intensity — you never relax against them.'' In 2004, the two teams served up one of the greatest games in league history, as the Revs' came back from three one-goal deficits before falling on penalty kicks in the semifinal. United went on to lift the title in what was Nowak's first year at the helm.

HOUSTON vs. COLORADO
Sunday, 7 pm, Fox Soccer Channel & HDNet (live)
The San Jose Earthquakes won the 2001 and 2003 MLS titles. Last season, they were the dominant team of the regular season before being upset in the first round of the playoffs by Los Angeles. The Quakes became the Houston Dynamo in 2006 and its regular season was less convincing than in 2005, but Coach Dominic Kinnear's squad is a game away from the final, entering the semifinal after an impressive comeback against Chivas USA. The Dynamo has the home-field advantage. But Colorado's performance in Dallas last week, in which Argentine Nico Hernandez scored twice while the Rapids' overcome a one-goal deficit to win, 3-2, before clinching on penalty kicks, proves they're comfortable on the road. ''We have no reason to be afraid,'' Kinnear told the Houston Chronicle. ''This is our place, and we expect a good crowd. But we do have to respect them because they are a good team.''