Seattle (16-7-3) won its third consecutive game to remain atop the Western Conference, while Chivas USA (6-14-6) had its winless streak reach eight matches.
Martins started the scoring for Seattle. He cleaned up Brad Evans' corner kick in the 11th minute and added a simple goal 5 minutes later. Seattle made it 3-0 when Rose redirected Evans' free kick it in the 38th minute. The duo combined on another free kick 4 minutes later for Evans' third assist of the first half.