Christian Benteke found the net, but United is winless in its past seven MLS matches and its past eight in all competition.
D.C. United has become more competitive under interim coach Kevin Flanagan, but mistakes and a glaring absence of attacking threats continue to mar close matches.
Saturday night’s 2-1 away loss to the Columbus Crew was the same margin as the previous two setbacks, extending United’s winless streak to seven in MLS and eight in all competitions.