SEATTLE — As the final whistle sounded, Stefan Frei jumped into a crouching position on top of the crossbar of the goal he cleanly defended for 90 minutes, and yelled at a mob of rabidly-cheering Sounders fans.

With a T-shirt wrapped around his head, and one of his sons in his arm, Clint Dempsey could not hide his overwhelming excitement. Neither could teammates, who ran around and grabbed one another for embraces.

It was Seattle’s time again to rule the Western Conference of Major League Soccer.

Next up — is it the Sounders’ destiny to win another MLS Cup?

Surely, Seattle is playing some of its best soccer of the season, and put that on full display in a dominating 3-0 victory over Houston on Thursday night in front of 45,298 at CenturyLink Field.

Combining their earlier 2-0 victory in Houston, the Sounders captured the two-leg conference finals playoffs series by a 5-0 aggregate tally.

Now, they travel once again to Toronto for a Dec. 9 rematch in the MLS Cup.

“It comes down to the players just wanting it,” Sounders coach Brian Schmetzer said. “They want another championship.”

It will be just the third time in MLS history two clubs have played each other in back-to-back championship matches. The other two were New England-Houston (2006-07) and the Los Angeles Galaxy-Houston (2011-12).

And in those previous two MLS Cup rematches, the same club won (Houston in 2007 and Los Angeles in 2012).

“I said this after last year, you get these opportunities possibly once in a lifetime — and we got it last year,” Frei said. “One year later, we’ve found ourselves with the same opportunity … and it would be amazing to do something similar.”

But first, the Sounders needed to take care of business against the Dynamo at home Thursday night.

And they wasted no time doing that.

Again, it was former Dynamo forward Will Bruin in the middle of everything. In the 22nd minute, he took a pass from Victor Rodriguez just outside the penalty box.

With his back to the goal, Bruin faked retreating back out, then delivered a back-footed pass through traffic, and right to a streaking Rodriguez near the 6-yard box.

“I saw him coming out of the corner of my eye, but I didn’t know if he was going to stay onside or not,” Bruin said. “It worked out.”

Indeed, it did. Rodriguez waited for Houston goalkeeper Joe Willis to make a move out, then rifled a shot past him inside left post for a 1-0 Sounders lead.

Essentially, at that point, the series was all but over.

But Seattle kept piling it on.

Early in the second half, Rodriguez led a Seattle break, getting it to Joevin Jones along the left side.

Jones laid a perfect cross at Dempsey’s feet along the right post, and the veteran tapped it in for his third playoff goal of 2017, which is a career-high, in the 57th minute.

After that, things got testy between the two sides — enough that another red card was issued.

After Jordy Delem, who came on as a reserve for Seattle, hit the turf, Houston’s Tomas Martinez came over and shoved Delem’s head into the ground.

After a video review, Martinez was ejected in the 66th minute, and the Dynamo was left to finish the match with 10 players.

Seven minutes later, the Sounders tallied their final goal as Bruin took a feed from Harry Shipp, and nudged a shot past Willis for his second playoff goal in as many games.

In four playoff matches, Seattle has scored seven goals, and allowed none.

In fact, dating back to the second leg of the 2016 Western Conference finals at Colorado, the Sounders have held an opponent scoreless for six consecutive playoff matches, an MLS record. That is 647 minutes … and counting.

“The last two games are some of the best games we’ve played all year,” Frei said. “That bodes well for next week.”