New York City FC and Portland finished on top of their respective conferences in 2017, but the teams' 2018 campaigns have gotten off to very different starts.
The Blues are undefeated through five games and have a league-leading 17 points, four clear of second-place Atlanta United in the Eastern Conference.
Portland has won only once and is mired in 11th place in the Western Conference.
But the Timbers (1-3-2) have played only once at home and host NYCFC (5-0-2) on Sunday at Providence Park in Portland.
The Timbers, who played their first five games of the season on the road, broke through in their home debut last Sunday.
Alvas Powell, who was named MLS Player of the Week, put Portland on the board early as the Timbers twice took two-goal leads and hung on to beat Minnesota United 3-2.
The sellout crowd of more than 21,000 helped the cause.
"The energy tonight from the fans gave us what we needed to fight all the way to the end and get the result that we needed," Timbers coach Giovanni Savarese said.
Powell followed his 21st-minute goal with an assist as Diego Valeri doubled the Timbers' lead two minutes later.
Savarese said he believes his team can progress after the win, especially at home, where the Timbers have lost only 12 times in the last five years.
"It's always better to build off victories," Savarese said. "The environment, the spirit after this match (against Minnesota) has been very good.
"It's an important match that we needed, especially playing at home with our fans. There was a lot of things that we did, some things we need to improve, but overall it was a very positive day."
Portland will need to improve to beat the league's best team.
NYCFC became the 12th team in MLS history and first in four years to remain unbeaten through seven games.
"They've had a great start," Savarese said. "They've been working for three years to build this team and now I think they feel like they are the closest to what they are looking for. They're very strong. It's going to be a tough test for us, but a great test."
The Blues have a league-leading 16 goals thus far, despite star striker David Villa missing three games.
The 36-year-old captain, who has dealt with a calf injury, scored his 399th career goal on Sunday against Atlanta.
"David looked good when he came on," Blues coach Patrick Vieira said after the 2-2 draw in Atlanta. "He just showed how he's been working with us the last couple of weeks and he came through with no issues, so we're happy."
Villa would become the fifth active player with at least 400 goals. Barcelona's Lionel Messi and Real Madrid's Cristiano Ronaldo have surpassed 600; Barcelona's Luis Suarez and the LA Galaxy's Zlatan Ibrahimovic are the other two players with more than 400.
