Sporting Kansas City and the Portland Timbers kept the pressure on in the MLS Western Conference, while Atlanta United claimed another win.
Goals from Daniel Salloi and Diego Rubio helped Sporting KC to a 2-1 home victory against the LA Galaxy on Sunday.
Salloi poked in the opener in the 18th minute before Rubio tapped in a Seth Sinovic pass in the first half for Peter Vermes' men.
Romain Alessandrini pulled a goal back for Galaxy but they were unable to find another at Children's Mercy Park.
Sporting KC is third in the Western Conference, a point adrift of the first-place Vancouver Whitecaps.
Sitting second is Portland, which recorded a 3-0 win over a nine-man Orlando City side.
Diego Valeri opened the scoring from the penalty spot to extend his MLS-record scoring streak to nine matches.
Darren Mattocks doubled the lead before Jonathan Spector was sent off for Orlando early in the second half.
Valeri struck again prior to the hour mark and substitute PC also saw red for Orlando.
That's goal Number 20 of 2017 for El Maestro, the most by a Timber in a single campaign across all eras. @DiegoDv8 #RCTID #PORvORL pic.twitter.com/tl131fzaFI — Portland Timbers (@TimbersFC) September 25, 2017
Meanwhile, Atlanta extended its unbeaten run to six matches with a 2-0 win at home over the Montreal Impact behind strikes from Hector Villalba and Jeff Larentowicz.
With Sunday's results, New York City FC became the second team to clinch a playoff slot after Toronto FC secured its spot earlier this month.