There were no surprises in Kansas City, where Supporters' Shield leader LAFC scored four second-half goals to complete a crushing victory midweek.
LAFC led 1-0 at half-time through Christian Ramirez's 28th-minute opener and the visitors put Sporting KC to the sword after the break at Children's Mercy Park.
Diego Rossi doubled the lead five minutes into the second half before Carlos Vela made it 3-0 in the 63rd minute, with Rodolfo Zelaya restoring LAFC's three-goal advantage after Yohan Croizet pulled one back for the host – who had an 82nd-minute penalty saved by Pablo Sisniega.
LAFC – nine points clear in the Western Conference – added some gloss to the scoreline via Mohamed El Monir in stoppage time as Bob Bradley's side made it nine wins in 10 games.
MLS champion Atlanta was humbled 5-1 by Chicago after playing the remaining 79 minutes with 10 men.
Leandro Gonzalez Pirez was sent off for a handball in the 11th minute as Atlanta already trailed the Fire 2-0 in Chicago.
And Frank de Boer's men were no match for the Fire, who added another three goals before half-time via Nicolas Gaitan, Charles Sapong and Fabian Herbers.
Brandon Vazquez converted a penalty approaching the hour mark to pull a goal back for Atlanta, who are fourth in the Eastern Conference, while the Fire are eighth and a point adrift of the play-off places.
Elsewhere, New York City extended its unbeaten streak to 14 games in all competitions by beating Seattle Sounders 3-0, Houston Dynamo snapped its losing run with a 4-0 drubbing of New York Red Bulls, Eastern Conference leader Philadelphia Union was 3-1 winner over Orlando City, Minnesota United trumped San Jose Earthquakes 3-1 and Real Salt Lake edged Columbus Crew 1-0.