Clint Dempsey got on the scoresheet as the Seattle Sounders defeated Houston Dynamo 3-0 to set up a repeat MLS Cup final showdown with Toronto FC on Thursday.

Veteran striker Dempsey rammed in Seattle's second goal of the night as the defending champions completed an emphatic 5-0 aggregate victory to advance.

They will face Toronto in Canada on December 9 in a repeat of the 2016 final, which Seattle won on penalties.

The Sounders had taken a stranglehold on the Western Conference final after winning last week's first leg 2-0 in Houston.

And any hope of a Houston comeback was snuffed out after 22 minutes when Victor Rodriguez played a superb one-two with Will Bruin before tucking away his finish.

Dempsey then doubled Seattle's lead in the 57th minute with another well-worked goal that put the Sounders 4-0 ahead on aggregate.

Joevin Jones found space down the left flank and calmly stroked a low cross into the path of Dempsey, who stabbed home a low shot.

As Houston's frustration grew, the match threatened to turn ugly and Tomas Martinez was given a red card for a violent shove on a Seattle opponent in the 66th minute.

Bruin made it 3-0 in the 73rd minute, catching the Houston defense cold before lifting a deft chip over the advancing Dynamo goalkeeper Joe Willis.

The win means Seattle will now have the chance to become the first team since the Los Angeles Galaxy in 2011 and 2012 to successfully defend the trophy.