D.C. United scored goals two minutes apart in the second half on Saturday to stop Toronto FC's unbeaten streak at six games.
All-time leading Major League Soccer scorer Jaime Moreno converted a penalty kick in the 70th minute and Luciano Emilio followed with a rebound goal in a 3-2 win at RFK Stadium in Washington.
Gonzalo Peralta also scored for United (3-7), which snapped a four-game losing streak.
Danny Dichio scored both goals for Toronto, which led 2-1 after the first half despite allowing more scoring chances than D.C. Toronto FC went on a franchise-best 4-0-2 string after losing 4-1 at the same venue last month.
Included in the streak was a 1-0 win over D.C. United earlier in the week.
United had some sustained pressure and a pair of corner kicks early in the match but could not convert. Toronto's Laurent Robert moved the ball upfield quickly, with Jim Brennan's cross placed perfectly for Dichio's header in the 12th minute.
The visitors had a favourable odd-man rush not long after but could not get a great scoring chance, with Amado Guevera's attempt deflected harmlessly.
D.C. gained momentum from the near-miss and their best chance came from the foot of Moreno, but Greg Sutton made a great diving save in the 28th minute.
Sutton was strong five minutes later, stopping Marcelo Gallardo's blistering shot with his gloves. Bryan Namoff's follow-up attempt sailed just over the crossbar.
The home side finally scored in the 41st minute, off a corner kick. Devon McTavish and then Peralta headed the ball past the Toronto defenders and keeper. It was the first goal Toronto had allowed in three games.
D.C. was picking up steam but it was Toronto leading by the half. Dichio took a set-up from Guevara and placed the ball inside the left post past keeper Zach Wells for his fourth of the season.
D.C. kept the pressure on in the second with Gallardo's shot hitting the bar and sailing out at the 54-minute mark.
Moreno buried his 115th career goal and fourth of the season on the penalty kick, outguessing Sutton. Toronto's Marvell Wynne had been cited for pushing down Santino Quaranta in the box. Quaranta was again the instigator of the winning goal.
His shot was too hot for Sutton to handle, and the keeper allowed a juicy rebound to Emilio, who made no mistake.
Wells did his job in the other net, deflecting Jarrod Smith's header wide late in the game. Robert was given a red card in the dying seconds for abusive language.
D.C. outshot Toronto 15-10 and held an 8-3 advantage in shots on goal.
Toronto FC will play the Montreal Impact of the United Soccer League on Tuesday as part of the inaugural Canadian Champions League tourney.
Toronto's next MLS action will be at home against the Los Angeles Galaxy on May 31.
Both games will be broadcast on CBC-TV and CBCSports.ca.