New York Red Bulls claimed back-to-back wins after accounting for Western Conference leaders FC Dallas 4-0 in MLS on Friday.
The Red Bulls continued their good run of form thanks to goals from Lloyd Sam, Sacha Kljestan, Mike Grella and Felipe Martins, having lost four games on the bounce previously.
New York's near flawless display - helping them improve to nine points alongside New England Revolution, DC United and Orlando City - condemned Dallas to back-to-back defeats.
Dallas' grip atop the west, which is a one-point lead, could evaporate when second-placed Colorado Rapids face Montreal Impact on Saturday.
Sam set the tone at Red Bull Arena, after heading home from inside the six-yard box following a well-executed set-piece.
The score remained the same until Kljestan doubled the lead seven minutes into the second half, heading home the rebound after Sam audacious long-range effort hit the crossbar.
Grella made it 3-0 with 19 minutes remaining, when he directed a bullet header past Dallas goalkeeper Jesse Gonzalez, and Martins capped the scoring in the 83rd minute.