The Seattle Sounders and Colorado Rapids each squandered an early lead and had to settle for a tie in their last game.
In their first matchup of the season, each Western Conference contender will look to bolster its respective position in the standings on Saturday night at Dick's Stadium.
Seattle (4-2-3) went up 1-0 in the 18th minute of last Saturday's match with FC Dallas on Jhon Kennedy Hurtado's first MLS goal.
The Sounders, though, finished with their third consecutive 1-all draw as Dallas tied the match in first-half stoppage time on a score from Andre Rocha.
Seattle, second in the West behind Chivas USA, fell to 4-0-2 when it scores first.
"We're upset and frustrated," Nate Jaqua said after notching his team-leading third assist. "We did enough to win the game and we didn't put the game away. We definitely learned something from it."
The Sounders, 1-0-3 in their last four matches, were without Freddie Ljungberg due to a migraine headache. The 32-year-old midfielder is expected to play against the Rapids.
"I thought we were a little disjointed," said Sounders coach Sigi Schmid, who is 14-9-6 all-time versus Colorado. "We had a couple new guys playing, but at the end of the day it's no excuse we should have put the game away in the first half."
Seattle has struggled putting the ball in the net lately, scoring just five goals in its last six matches after notching seven during its 3-0-0 start.
Midfielder Brad Evans nearly scored in the 36th minute with a shot inside the penalty box, but the ball ricocheted off the left post. He also sprained his left ankle during last week's match, and could miss his first action of the season Saturday.
Defender Zach Scott remains out with a groin injury for the Sounders, but James Riley will return after missing the Dallas match with a red-card suspension.
Colorado returns home following last week's 1-all draw at New England. Conor Casey recorded his fifth goal of the season in the third minute off a ball from Jordan Harvey, but the Rapids (3-2-3) could not hold the lead as Steve Ralston drove in a penalty kick in the 18th minute.
Colorado lost despite outshooting the Revolution 15-6 and taking a season-high 10 corner kicks.
"I expect a little too much," said Rapids coach Gary Smith, whose team is 1-0-2 in its last three games. "With our bright start, we may have set some stronger foundations for the way the game moved on. To their credit, they got back in it. We took a long time adjusting to the slippery turf, the surface."
Casey is tied for second in MLS in goals but faces a challenge in Seattle goaltender Kasey Keller, whose 0.41 goals-against average leads the league.
Colorado is 2-0-1 at home this season.
The Rapids travel to Tukwila, Wash., on Tuesday to face the Sounders at Starfire Sports Complex in a play-in match for the Lamar Hunt U.S. Open Cup. The teams have one more regular-season match -- June 28 at Qwest Field.
Copyright 2009 by The Associated Press