SEATTLE >> Two down, one to go for the Seattle Sounders.

Second-half substitute Marco Pappa scored in the 85th minute and again in stoppage time, and the Sounders beat the Los Angeles Galaxy 2-0 on Saturday to win the MLS Supporters’ Shield for the first time in the six-year history of the club.

The Sounders (20-10-4, 64 points) and Galaxy (17-7-10, 61 points) started the day in a tie atop the overall standings. Seattle had more wins, so it only needed a tie to claim the Shield, while Los Angeles needed a victory to take the honor for the fifth time.

“It was great to win, and to win the game at the end like that,” Sounders coach Sigi Schmid said. “Obviously, a tie would have gotten the Shield as well, but this gives it a little more pizazz.”

The Sounders now have two parts of the so-called treble – the U.S. Open Cup, which they won last month for the fourth time, and the Supporters’ Shield. The one part that remains is the MLS Cup.

“Our mantra this season is we’re going to try to be greedy,” Schmid said. “We have one more thing before we’re the ultimate greedy people.”

Seattle’s first goal began with a quick free kick 35 yards from the net. Obafemi Martins sent a ball into the penalty area. Pappa ran in from the left side, beat Galaxy goalkeeper Jaime Penedo to the kick and drilled it into the back right corner for the score.

“I was suspecting Oba would give me the ball,” Pappa said. “I’m happy he saw me – I was wide open.”

Pappa also helped the Sounders last Sunday when he entered in the second half and Seattle rallied from two goals down at Los Angeles to pull out a 2-2 tie.

“I’m the kind of player who always likes to play, for sure, but I have to respect the coach’s decision,” Pappa said. “I’m happy not just for me, but more for the team.”

Sounders goalkeeper Stefan Frei preserved the lead early in stoppage time by saving Dan Gargan’s point-blank drive from 10 yards. Pappa then clinched the win by stealing the ball from Penedo outside the top of the box, taking it in and tapping it into the wide-open net, giving him six goals for the season.

Los Angeles was without 19-goal scorer Robbie Keane, who rested with what coach Bruce Arena said was “a few nagging injuries.” But the Galaxy controlled the action for much of the game, outshooting Seattle 13-4, and not even allowing a Sounders shot until the 76th minute.

“Obviously, we were a little unlucky. At worst, we should have come out of here with a point,” Arena said. “But that’s life, that’s soccer. We controlled the game, but we needed to be a little more dangerous in the last third of the field. They keep a lot of players back with us, and they play it pretty safe.”

Galaxy star Landon Donovan, who announced his retirement on Aug. 7, played his final regular-season game. But he has at least two postseason games left in his distinguished career.

“We can’t play a whole lot better than that,” Donovan said. “(The Shield) could have been ours. But we gave up too many points early in the year, and that came back to hurt us.”

“That being said, we played very well tonight,” he added, “and if we play like that in the playoffs, there’s a good chance we’re going to be holding a trophy at the end.”