SEATTLE — This time, Chad Marshall made sure the goal was credited to him.

Marshall headed in a corner kick in the 24th minute, and the Seattle Sounders beat the Chicago Fire 1-0 on Wednesday night to get back into the MLS playoff picture.

The Sounders (12-13-5) have 41 points and climbed into a tie with idle Portland for the sixth and final playoff berth in the Western Conference. Seattle still has one game at hand on the defending champion Timbers, and also has one more victory, thanks in part to its current three-game winning streak.

That included Sunday’s 4-2 triumph against the Galaxy in Los Angeles. Total wins is the first tiebreaker.

“Obviously, Sunday was an emotional win, a huge win for us,” Marshall said. “I don’t think tonight was our best soccer by any means. But we were able to grind it out and get a result, and that’s a huge three points at this time of year.”

Marshall, whose four goals for the year equals his output for the last four seasons combined, thought he scored the equalizer in L.A. on Sunday when the Sounders were down 1-0. It ultimately was ruled an own goal.

But on Wednesday, there was no doubt it was his.

Andreas Ivanschitz set it up with a corner kick from the right side. The ball floated to the top right corner of the 6-yard box, and Marshall went up with a twisting header that went into the far side of the net, way beyond the reach of goalkeeper Sean Johnson

“That’s his game – that’s what he’s known for,” Marshall said of Ivanschitz. “He serves a great ball. It’s just a matter of making good runs. Fortunately, I was able to get on the end of it.”

Chicago (6-15-9) was eliminated from postseason contention. The Fire, with just one win in their last 40 road contests dating to July 2014 (1-23-16) have four games remaining and can finish with no more than 39 points. D.C. United is sixth in the East with 40 points after beating Columbus earlier Wednesday.

“I’m real disappointed and very sorry for our guys. I think we did a huge job to play against one of the best teams and play the way we wanted to play,” Chicago coach Veljko Paunovic said. “I think the game plan worked well. Unfortunately, we conceded that goal. It hasn’t happened too many times this year on set pieces. We had opportunities, which we had to convert better.”

One of those came in the 31st minute when Fire leading scorer David Accam had a 14-yard shot from straight in front blocked by Sounders defender Tyrone Mears. The rebound went out Razvan Cocis, but his shot from the top of the arc was saved in front of the right post by Seattle goalkeeper Stefan Frei, who logged his seventh shutout.

Accam had another try from inside the box in the 38th minute, but Marshall got in front of that one.

“Our game in L.A. was such a massive victory, and they were a little flat tonight,” said Sounders interim head coach Brian Schmetzer, now 6-1-2 since taking over on July 26. “But I think that was to be expected. They somehow found a way to win, and that’s what you like about teams that can get in the playoffs and do some good things in the playoffs.”

Central defender Marshall now has the third-highest goal total on the team, behind the 12 of rookie forward Jordan Morris and eight of U.S. international Clint Dempsey. However, Dempsey’s season was declared finished by the Sounders on Tuesday. He has not played since Aug. 21 while being evaluated for an irregular heartbeat.