Stewart F. House, AP
Seattle Sounders midfielder Clint Dempsey (2) and FC Dallas defender Walker Zimmerman (25) battle for the ball during the second half of an MLS soccer game in Frisco, Texas on Saturday, Sept. 16, 2017. (Stewart F. House/The Dallas Morning News via AP)

SANDY — Since June 17 nobody in MLS has figured out how to beat Seattle, as the reigning MLS Cup champs have put together an impressive 13-game unbeaten streak with a 6-0-7 record over that stretch.

It’s something Real Salt Lake needs to figure out at Rio Tinto Stadium on Saturday (KMYU, 7:30 p.m.) to keep its playoff hopes alive.

RSL is tied for the last playoff spot in the Western Conference, but it has only four games remaining while the two teams it’s tied with — Houston and Dallas — each have six games remaining.

It can’t afford to drop any more points at home this season, and a win over Seattle would put extra pressure on Houston and Dallas, two teams that are limping to the finish line just like Real Salt Lake last season.

“We have to take care of every game that we have and then we can do a little scoreboard watching. It would be great to finish with four wins,” said RSL coach Mike Petke.

It starts on Saturday with Seattle, which has won three straight in the rivalry and four of the last five. The Sounders prevailed 1-0 in the other meeting this season at Century Link Field.

“They’re a very dangerous team, they have the longest unbeaten streak in MLS this year … they have power at almost every position, and they have quality at almost every position,” said Petke.

That being said, Seattle is winless with four straight ties and isn’t 100 percent heading into Saturday’s game with Jordan Morris out with a hamstring injury.

Salt Lake could be equally shorthanded up top as Luis Silva’s status is unclear after he exited last week’s win over Portland in the second half with a groin injury.

If Silva is unable to go Yura Movsisyan figures to get the starting nod for just the second time in the past 11 matches.

During those 11 matches Real Salt Lake has scored 27 goals, and whether Movsisyan or Silva gets the nod at striker it should be able to put pressure on a Seattle defense that’s given up just 11 goals during its 13-game unbeaten streak.

“They pose dangers all over the place, but I think we’re a pretty dangerous team as well,” said Petke.

Seattle’s attack starts with Clint Dempsey, who’s scored a team-high 11 goals. RSL center backs Justen Glad and Marcelo Silva need to be dialed in for 90 minutes to keep him in check.

The pairing was very sharp last weekend against Portland, but one brief hiccup allowed Diego Valeri to punish RSL with a second-half goal.

“They were very good last game except for one moment for Valeri’s goal, but that’s all it takes in this league is one moment. You have a guy like Dempsey who’s lethal,” said Petke.

After Saturday home game RSL’s next two games are on the road which adds to the urgency of picking up the full three points against Seattle.