Columbus' Hesmer has second straight shutout
Andy Iro scored in the 84th minute and Leandre Griffit, two minutes into his MLS debut, added another in the 90th.
Columbus (10-3-4) is first Eastern Conference. Houston (5-8-4) is 0-4-3 in the past seven games. Renteria took advantage of a blunder by Houston backup goalkeeper Tally Hall in the 34th minute.
Hall backpedaled as he tried to field a ball outside the penalty area and fell. Renteria picked up the loose ball and scored easily.
Houston defender Bobby Boswell received a second yellow card with 18 minutes left.