The Vancouver Whitecaps ended a five-match winless MLS run and booked an automatic berth in the Western Conference semi-finals.
Vancouver's late-season collapse saw them on the brink of missing out on a top-two finish, but a 3-0 win over the Houston Dynamo ended that run.
Kekuta Manneh, Kendall Watson and Robert Earnshaw were on target, with Dynamo having nothing to play for after being unable to challenge for a play-off spot.
It was the LA Galaxy who surrendered that second position, with a 2-1 loss to Sporting Kansas City meaning they finished fifth.
The Portland Timbers and Seattle Sounders picked up wins over the Colorado Rapids and Real Salt Lake respectively, booking their spots in the play-offs.
Darlington Nagbe's brace led the Timbers to a 4-1 win, while Clint Dempsey scored twice in the Sounders' 3-1 victory.
The Timbers finished third in the Western Conference, meaning they will play Sporting KC for a spot in the semi-finals while LA Galaxy face-off against the Sounders.
In other results, Dallas dashed any hopes the San Jose Earthquakes had of qualifying for the play-offs with a 2-1 victory in Texas.
In the Eastern Conference, Columbus Crew joined the New York Red Bulls as the two sides to automatically qualify for the semi-finals.
A 5-0 win over DC United saw Columbus move into second, condemning DC to fourth place and a play-off game against the New England Revolution.
Columbus scored four second-half goals, including a brace to Ethan Finlay, in a surprise win.
New England's 3-1 win over the out-of-contention New York City meant they moved above Toronto, who suffered a 2-1 loss to Montreal Impact.
Didier Drogba scored both of Montreal's goals against Toronto, with the two sides set to meet again on Thursday for a spot in the semi-finals.
Meanwhile, the Red Bulls clinched the 2015 Supporters' Shield thanks to a 2-1 win over the Chicago Fire.
In the other game, Sebastien Le Toux scored a penalty to give the Philadelphia Union a 1-0 win over Orlando City.
