Gyasi Zardes scored his 20th goal of the season in the 61st minute, helping the Columbus Crew beat the Supporters' Shield holder New York Red Bulls 1-0 on Sunday in the opening game of the Eastern Conference semifinals.
The second leg is next Sunday in Harrison, New Jersey.
Zardes had a sliding finish of a back-heel pass from second-half substitute Federico Higuain. It was Zardes' third career postseason goal.
New York goalkeeper Luis Robles denied Pedro Santos' open shot from distance in the 89th, and Steffen blocked Bradley Wright-Phillips' glancing header in stoppage time.
New York's best scoring chance came in the 27th minute when Tim Parker headed a corner kick off the post that deflected off Steffen and was cleared away.
Columbus entered off a penalty-kick shootout victory over D.C. United while New York had a bye following its third Supporters' Shield title in six seasons. The Crew are the only Eastern Conference team New York hasn't beaten this year.
The teams have met three previous times in the postseason with the Crew winning each one.
