Seattle Sounders have beaten DC United 1-0 in their MLS clash to extend their lead at the top of the Western Conference.

The hosts came close to scoring in the opening minutes of the match when Chris Rolfe fired over the bar, before Luis Silva saw a long-range effort saved by Stefan Frei.

Rolfe was inches away from giving his side the lead midway through the first half, but he fired his strike against the post.

In the 39th minute Seattle took the lead through Chad Barrett, who headed Gonzalo Pineda's cross into the top corner.

Marco Pappa saw an effort saved by Bill Hamid soon after the break, before Steve Birnbaum headed over when well placed.

United took control of possession as they searched for an equaliser, but they struggled to create any clear-cut chances.

In the final minute Eddie Johnson saw a shot saved by Frei, and it proved to be their final chance as Seattle held on to claim the three points.