Pablo Zeballos and Alejandro Vela scored during a first half during which the visitor didn't get a lot of the ball but used its possessions more efficiently than the home team.
Zeballos scored in the 14th minute after poking the ball away from defender Eric Brunner, who got a piece of a pass from Ramon Nunez intended for Zeballos but couldn't control it. Instead, Zeballos poked the ball past stranded keeper Will Hesmer.
Vela scored with a superb chip when Nunez played him into space on the left flank. Hesmer came out to close down the angle but with no other challenger in the vicinity, Vela lifted the ball over the keeper and it bounced unbothered into the net.
Los Cementeros lead Group C with a 3-1-0 (W-T-L) record and 10 points heading into a match Tuesday against Puerto Rico Islanders (0-2-2, 2 pts.) and need only a point to advance into the knockout phase. Cruz Azul romped to a 5-0 win when it played Columbus in Mexico City Aug. 26, yet the Crew (2-0-2, 6 pts.) can clinch a spot in the quarterfinals if it beats Deporivo Saprissa (1-1-2, 4 pts.) at home Tuesday.
Guillermo Barros Schelotto threatened several times with crosses and set plays. He hit the crossbar in the 41st minute and nicked the post with another effort midway through the second half. Goalkeeper Yosgart Guttierez foiled the Crew on several occasions; he thwarted Robbie Rogers near the end of the first half and dived left to deflect a hard, low shot by Duncan Oughton's shortly after the halftime break.
Emmanuel Ekpo and Emilio Renteria came on as subs early in the second half but despite their energy and movement the Crew couldn't break through. Renteria broke down the right flank and centered ball no teammate could reach, and he just failed to get his head on a Schelotto cross.
Schelotto sent another whistling free kick just wide of the post in the final minutes and fired a shot on goal in stoppage time. Guiterrez turned Schelotto's shot over the crossbar to record his seventh and final save of the match. A deflected shot by Ekpo produced a corner kick later in stoppage time, and the partially cleared ball bounced for Ekpo to settle, but his effort missed the near post.
D.C. United (1-0-2, 3 pts.) can move into a second-place tie with Marathon (2-1-0, 6 pts.) in Group B when it hosts the Honduran club at RFK Stadium Thursday (8 p.m. Eastern, Fox Soccer Channel).
Concacaf Champions League Group C
Sept. 23 in Columbus
Columbus 0, Cruz Azul 2.
Goals: Zeballos 14, Vela (Nunez) 39.
Columbus - Hesmer, Padula, O'Rourke, Brunner, Oughton (Ekpo, 54) Moffat, Gaven (Burns,77) Rogers, Schelotto, Lenhart (Renteria, 58), Moreno.
Cruz Azul - Gutierrez; Pinto, Huiqui, Velasco, Cervantes, Castro (Chavez, 67), Riveros, Nunez, Ortiz, Zeballos (Orozco, 62), Vela.
Referee: Geoffrey Hospedales.