Former United States international forward Chris Rolfe scored twice as Eastern Conference leaders DC United rallied past Real Salt Lake 6-4 in a topsy-turvy encounter.
Goals either side of the interval from Rolfe levelled proceedings, after RSL raced out to a 2-0 lead inside the first 21 minutes at Robert F. Kennedy Memorial Stadium, before Perry Kitchen and Nicholas DeLeon broke the tie and secured victory for United on Saturday.
United are nine points clear in the East, ahead of New York Red Bulls, who saw off Philadelphia Union 3-1 in Tranquillo Barnetta's debut for the conference strugglers.
RSL stormed out of the blocks in Washington via Joao Plata and Kyle Beckerman.
Plata side-footed the ball past goalkeeper Andrew Dykstra in the second minute and Beckerman got in on the action 19 minutes later with a powerful long-range strike.
Rolfe reduced the deficit three minutes shy of the break, and he then equalised from the penalty spot nine minutes into the second half.
United and RSL exchanged goals up until the 68th minute, as Aaron Maund cancelled out Taylor Kemp's thunderous effort, before Fabian Espindola restored the home team's lead seconds later, only for Abdoulie Mansally to hit back and make it 4-4.
That is as good as it got for RSL, with Kitchen heading United into a 79th-minute lead which would not be relinquished as DeLeon completed the scoring six minutes later.
There were also goals galore at Florida Citrus Bowl after Orlando City accounted for Columbus Crew 5-2.
Orlando overcame an early deficit as in-form rookie Cyle Larin's brace helped end a run of three straight league losses.
Reigning MLS Cup champions Los Angeles Galaxy and New England Revolution both posted 3-1 wins on Saturday.
Three unanswered goals in the second half from Sebastian Lletget, Alan Gordon and Robbie Keane inspired the Galaxy - third in the Western Conference - at Colorado Rapids.
The Revolution, meanwhile, won for the second time in three games, accounting for 10-man Toronto FC.
Elsewhere, Frank Lampard's long-awaited New York City debut ended in defeat as Montreal Impact emerged 3-2 victors in the Big Apple.
Free-falling Seattle Sounders crashed to a fourth consecutive defeat, beaten 3-0 at home to Western Conference high-flyers Vancouver Whitecaps, who stayed a point clear at the summit.
Sporting Kansas City and 10-man Houston Dynamo played out a 1-1 draw.
