Valdez’s header in 88th minute lifts the Sounders to 1-0 playoff victory

SEATTLE — The fight was on.

And it was interrupted — fortunately for the Seattle Sounders — by a thing of beauty.

It was almost exactly a year the last time the Sounders played in a Western Conference knockout round playoff match. Nelson Valdez tallied one of the team’s three goals in a victory.

And he had not scored since — until the 88th minute. It was the only goal scored as Seattle eliminated Sporting Kansas City, 1-0, on Thursday night in front of 36,151 at CenturyLink Field.

The Sounders are now 3-0 in the knockout round, all at home. They defeated Colorado, 2-0, in 2013 — and the Los Angeles Galaxy, 3-1, last season.

They will now move on to the conference semifinals to play FC Dallas. The first match of the two-leg series is Sunday in Seattle (6:30 p.m. PDT).

But first, Seattle had to survive a grueling, all-out assault by SKC, which is known for its rugged grabbing, tripping, pushing and whatever else doled-out punishment that comes with the sport.

Fouls happened everywhere, from both sides. Thirty were called. Many others were not.

“The playoffs are just a little bit different — a level higher,” Seattle coach Brian Schmetzer said.

And then came the decisive moment.

The ball had gone to the far side to defender Joevin Jones, who pushed it up before sending a bullet into the box.

And Valdez — who came in for Erik Friberg in the 79th minute — snuck past his man, went airborne, got his head on the cross and easily nudged it past SKC goalkeeper Tim Melia for the game-winner.

Schmetzer called it the Sounders’ “biggest goal of the season.”

“I can’t think of a better person to be rewarded for this moment, because he has worked so hard all year long,” Schmetzer said. “For him to come through in such a critical moment is well-deserved. He carried the team on his back here.”

The overjoyed 32-year-old striker from Paraguay sprinted back toward the Sounders bench. Teammates joined him, knowing how big of a moment it was in their season.

And also in Valdez’s tenure, which has been a little underwhelming up to this point. Many expected more goal-scoring from a forward who had played in two FIFA World Cups.

In his 24 games this season, mostly off the bench, he had fired off 30 shots. None of them had found the mark — until Thursday night.

“I’ve been feeling like a big mountain (was) on top of me for the whole season,” Valdez said through a team translator. “Finally, with that goal, that mountain went away. The pressure has been relieved.”

Schmetzer has heard the criticism of Valdez throughout the season, but countered that his player never wavered in his full effort and high-intensity work rate.

“He is a winner. He’s played in World Cups. The players respect him. The coaching staff respects him,” Schmetzer said. “He is just a really, really good human being.”

If you are a SKC supporter, the offsides call in the 53rd minute is one that will be hard to swallow.

Essentially, the play was almost identical to the Valdez goal. Benny Feilhaber sent in a pass that Matt Besler easily got his head well inside the penalty box, and the ball rolled inside the right post.

But it was immediately waved off, keeping the match scoreless.

After the match, SKC coach Peter Vermes was fuming over how the match was officiated. His biggest gripes were over those two plays.

He added that Besler was legal on his non-goal, and that Valdez was much closer to being offsides on his goal.

Vermes went as far to say that Major League Soccer owned his organization an apology.

“This game was taken away from us today,” Vermes said.

SKC had the stronger scoring chances in the first half. Its best trip came in the 10th minute when Paulo Nagamura ripped a shot just inside the penalty box that Stefan Frei tracked — and knocked away.

The loose ball came to Dom Dwyer, whose attempt from the right side clanked off the left post.

Frei was nothing short of brilliant, deflecting shots with every part of his body. He was credited with seven saves.

“He kept us in the game,” Schmetzer said.