In front of a little more than 48,000 spectators Stewart started reasonably well and was fourth around the opening turns. He needed another two laps before he relegated Ryan Villopoto and was then able to control the remaining 17 circulations in the 16 minute sprint.
The 2009 edition was the 44th Supercross meeting to be held in Houston with Pierre Karsmakers winning the inaugural event in 1974 with a Yamaha. Stewart's success increased Yamaha's tally to 15 triumphs in the State since the mid-1970s. In taking the chequered flag he also registered the 27th AMA SX win of his career.
"The bike was definitely better this weekend," he said. "I just felt more comfortable when we first got here, and we changed some stuff, and it's coming along. I think it was definitely a better weekend for me, and I'm just going to try and keep on improving and see what happens."
Supercross class rookie Joe Gibbs Racing's Josh Grant finished fifth to maintain his streak of a top five finish in each round so far. "I told myself coming into this season that I wanted to be top-five every weekend, and so far, I've been better than that," he reflected. "We had two good races at the beginning, and that's about it, but the last two tracks, I haven't really felt comfortable on, so for me to not feel comfortable on a track and still get top-five and still ride the way I've been riding is good."
Stewart has risen from fourth to second in the standings and now lies just 9 points behind leader Reed. Grant is in third place but level on points with his brand-mate.
Round five takes place next weekend at the AT&T Park in San Francisco.