Vancouver Whitecaps missed the chance to overhaul LA Galaxy at the top of the MLS Western Conference, while the East's chasing pack increased the pressure on DC United.
After Galaxy (46 points) lost Friday's California Clasico 1-0 at San Jose Earthquakes, Vancouver (45) knew a draw would be enough for them to claim pole position in the West's standings but Houston Dynamo denied them on Saturday.
Ricardo Clark and Raul Rodriguez scored the goals in Houston's 2-0 win, while the Whitecaps finished the match with just nine players as Kendall Waston and Matias Laba received second yellow cards after half-time.
The Dynamo had not won in three league matches but were unbeaten in five games at their BBVA Compass Stadium, with Clark continuing Houston's strong form at home when he pounced on a loose ball in the penalty area in the 34th minute.
Rodriguez capped off Houston's win with a header with three minutes left.
In the Eastern Conference, Columbus Crew moved within three points of faltering leaders DC with a 2-1 win at New York City, while Toronto FC and New England Revolution also won to stay in touch with top spot.
Federico Higuain put the Crew in front with a header from a corner after just nine minutes but the hosts were level by the half-hour mark thanks to Andrew Jacobson's 20-yard drive.
Frank Lampard made just his third appearance for the home team but was withdrawn on the hour mark, before Justin Meram struck the winner for Columbus with seven minutes remaining, placing his shot inside the far post after dribbling inside from the left flank.
The win took the second-placed Crew to 41 points in the East, just three behind DC, who have lost their past two matches and travel to third-placed New York Red Bulls (39) on Sunday.
Toronto and New England (both 37) remain in contention after wins over Montreal Impact (2-1) and Philadelphia Union (1-0), respectively.
FC Dallas ended their three-game losing streak with a 2-0 triumph over Real Salt Lake, while Colorado Rapids defeated Sporting Kansas City 2-1.
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