The MLS side only needs a draw at Arabe Unido in next month's group stage finale to advance to the CONCACAF Champions League quarterfinals.
Behind goals from Jason Johnson and Bobby Boswell, the Dynamo took control of the group Wednesday with a 2-0 win at home over Trinidad and Tobago's W Connection.
With the victory, Houston (2-0-1) has a one-point lead on Arabe Unido heading into the teams' meeting in Panama on Oct. 24. The Dynamo need just a draw in that match to advance to the quarterfinals next spring.
Despite fielding a largely second-choice squad, the Dynamo came out firing Wednesday. They nearly went ahead midway through the first half when Cam Weaver struck the crossbar and Kofi Sarkodie had a shot cleared off the line.
Houston took its deserved lead in the 40th minute. Pouncing on a W Connection giveaway, Johnson took a touch around a defender before hammering in his shot from the left side of the box.
Boswell doubled the lead six minutes after halftime. Making a near-post run on an Alexander Lopez corner, Boswell nodded a shot that glanced off the defender manning the post and went in.