Real Salt Lake beat the New England Revolution 2-1 despite playing more than half an hour with ten men to pull level with the San Jose Earthquakes at the top of the Western Conference.
The Revolution opened the scoring in the 22nd minute through Blake Brettschneider, but a brace from Alvaro Saborio in the 33rd and 55th minutes turned the match around.
Will Johnson was dismissed in the 59th minute, but the numbers were evened up nine minutes from the end when substitute Fernando Cardenas saw red.
It allowed Real to draw level with the Earthquakes, who slipped to a last-gasp defeat at the Vancouver Whitecaps.
San Jose led through Chris Wondolowski's 15th-minute opener, but Gershon Koffie levelled five minutes before the break and substitute Eric Hassli stunned the Quakes in the dying moments.
Eastern Conference leaders Sporting Kansas City saw their lead cut to three points as they suffered just their second defeat of the season, 2-0 at home to the Montreal Impact.
Felipe Martins scored on the half hour mark, and Patrice Bernier made it 2-0 from the spot in the 63rd minute.
DC United took advantage to narrow the gap with a 2-0 win at Toronto FC thanks to second-half goals from Chris Pontius and substitute Hamdi Salihi.
Joel Lindpere scored the only goal in the 19th minute as the New York Red Bulls won 1-0 at the Los Angeles Galaxy, while Mauro Rosales' 63rd-minute effort saw the Seattle Sounders beat the Philadelphia Union by the same scoreline.