TUKWILA — The goal celebrations were somewhat subdued.

Sounders FC forward Kenny Cooper scored twice, including a crowd-pleasing bicycle kick, and Seattle also got goals from Brad Evans, Zach Scott and Sean Okoli on Wednesday, cruising to a 5-0 win against PSA Elite in the fourth round of the U.S. Open Cup.

This, of course, was supposed to happen in one of the most lopsided matchups in the tournament — an amateur team versus the top team in MLS and three-time Open Cup champion — which explains why the Sounders didn’t cheer their own efforts to the same vigor as the 3,718 at Starfire Stadium.

“I thought it was a … workmanlike effort,” Scott said. “It’s very easy to let your guard down with teams like this.”

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Seattle will take on someone its own size in the fifth round, hosting the San Jose Earthquakes here at 7:30 p.m. Tuesday.

Leading 3-0 in the second half, Cooper added a highlight to the blowout in the 56th minute. The chance was created when Scott battled PSA goalkeeper Earl Edwards, Jr., for a loose ball, which eventually bounced to Cooper for a dazzling overhead shot.

“Just got my foot on it, and it was lucky — ended up in the back of the net,” said the understated Cooper.

Scott quipped: “He’s a pretty agile guy for a big dude.”

Okoli capped the scoring in the 85th minute, tapping in a cross from substitute Chad Barrett as the Sounders matched their largest margin of victory in all competitions (MLS, Open Cup, CONCACAF Champions League).

Seattle improved to 15-0 at home in the Open Cup, with a 42-8 goal differential.

“Obviously we weren’t happy with how we started the Open Cup last year,” said coach Sigi Schmid, whose team lost its first game in 2013, “so we wanted to make sure that we got off to a batter start.”

The Sounders took the lead in the 23rd minute, a chance set up when Aaron Kovar intercepted an errant PSA pass and drew a penalty kick on a darting run. Evans, who is 7 for 7 on PK attempts in MLS, stepped up and drilled a low shot to the left of Edwards.

Seattle doubled the lead in the 40th minute when Scott leaped high to head in a corner kick from Kovar, who impressed in his first competitive action for the Sounders.

“It’s not very hard to hit corners when you have guys like Zach and Cam (Weaver) and Kenny Cooper,” said Kovar, who still had rookie duty of carrying the ball bag after the game. “(They’re) big targets, and I put it in the air where they can get to it.”

Scott said he didn’t even see the shot go in: “I just heard everybody cheer, so that was really nice.”

Cooper scored on a header to make it 3-0 just before halftime, and the advantage could have been far worse at the break due to the game’s one-sided nature. PSA Elite, based in Irvine, Calif., was the last remaining amateur team in the field and didn’t record a shot until the 49th minute.

The Sounders fielded a fairly strong lineup considering the mismatch, starting regulars like Evans, Cooper and Leo Gonzalez.

“We talked about not giving them a chance, not allowing them to hang around during the game,” Schmid said, “getting some goals in the first half and putting it away.”


• Tickets for the San Jose game go on sale to the public at 10 a.m. Friday, earlier for season-ticket holders and members of supporters groups.