The quarterfinals of the U.S. Open Cup produced heroes in unlikely roles. Landon Donovan was the supersub for the Los Angeles Galaxy, and Jamil Walker made the most a rare start for D.C. United.

Donovan, who came on the 37th minute, scored twice in overtime to give the Galaxy a 3-1 victory over the Colorado Rapids, its first over Colorado after three 1-0 losses in MLS play. Teenager Quavas Kirk equalized for Los Angeles just before halftime after the Rapids' Clint Mathis had opened the scoring in the third minute.

For the second straight Open Cup game, Walker, starting in place of star Jaime Moreno, was the difference for D.C. United. Walker's two second-half goals broke a 1-1 tie and gave United a 3-1 victory over the New York Red Bulls, spoiling Red Bulls coach Bruce Arena's return to RFK Stadium. Walker, who hasn't scored for United since late April in MLS action, also had the winning goal against the Columbus Crew in their fourth-round Open Cup match.

The first two goals in the United-Red Bulls game came late in the first half. Josh Gros scored for United in the 37th minute, and Amado Guevara equalized for New York in the 42nd minute. Moreno, who later came on as a substitute, was one of four United all-stars who didn't start. The game drew 8,637 fans, the largest crowd for the four quarterfinals.

-- The Houston Dynamo remains alive in its bid to win the Open Cup for the first time after beating FC Dallas, 3-0. Goals by Eddie Robinson, Alejandro Moreno and Chris Wondolowski gave the Dynamo the convincing victory. Trinidad & Tobago World Cup goalie Shaka Hislop didn't make a save in his FCD debut.

-- Costa Rican Andy Herron scored twice for the three-time champion Chicago Fire in its 2-1 win over the New England Revolution. Taylor Twellman scored the lone goal for the Revolution.

U.S. OPEN CUP SEMIFINALS
Sept. 6 in Bridgeview, Ill.
Chicago Fire (MLS) vs. D.C. United (MLS)
Sept. 6 in Carson, Calif.
Los Angeles Galaxy (MLS) vs. Houston Dynamo (MLS)