James Stewart picked up his fifth win from six AMA starts to further extend his championship advantage, in front of 49,973 fans, at Houston's Reliant Stadium.

Kawasaki team-mate Tim Ferry took the $1,500 Progressive Direct Holeshot Award while Stewart made his way through the field after a sixth-place start. As has been the case most of the season, Stewart struck early and often and reached the lead on lap six.

Once in front, Stewart cruised to an easy win by a comfortable 17.316secs margin over nearest championship rival Chad Reed, while Ferry was third.

"I had a big crash earlier in practice and knew that this track could come back and bite me," said Stewart, who moved into a tie for tenth on the all-time series win list, with Supercross legend Jean-Michele Bayle, after his 16th AMA victory. "I have a points lead but can't afford to back down because things can get bad when you start to let up."

Stewart now holds a 21-point margin over Yamaha star Reed in the Amp'd Mobile AMA Supercross Series and an 18-point lead over the Australian in the Amp'd Mobile World Supercross GP standings.

In the Supercross Lites class another Kawasaki star, Ryan Villopoto, started the main event in style by narrowly edging out the Yamaha of Jason Lawrence - but the championship leader then fell on lap six, handing the lead to Lawrence.

Lawrence kept the top spot until being chased down by Villopoto, who regrouped and held on to take the win, his fifth of the season. Lawrence finished second while Honda's Josh Grant was third.

"(A lapped rider) just jumped right off the table top, hit a tuff block and went down right in front of me," said Villopoto in reference to his crash on lap six. "I had nowhere to go and ran right into him. I got back up and chased (Lawrence) down for the win."

The next round of Amp'd Mobile Supercross takes place on Saturday, February 17, at San Diego's Qualcomm Stadium.

Amp'd Mobile AMA Supercross Series Event Results, Houston:
1. James Stewart, Haines City, Fla., Kawasaki
2. Chad Reed, Tampa, Fla., Yamaha
3. Timmy Ferry, Largo, Fla., Kawasaki
4. Kevin Windham, Centerville, Miss., Honda
5. Travis Preston, Hesperia, Calif., Honda
6. Michael Byrne, Newnan, Ga., Suzuki
7. Heath Voss, Mico, Texas, Honda
8. Ivan Tedesco, Murrieta, Calif., Suzuki
9. Paul Carpenter, Ithaca, N.Y., Kawasaki
10. David Vuillemin, Menifee, Calif., Honda

Amp'd Mobile AMA Supercross Series Season Standings:
1. James Stewart, Haines City, Fla., Kawasaki, 147
2. Chad Reed, Tampa, Fla., Yamaha, 126
3. Timmy Ferry, Largo, Fla., Kawasaki, 110
4. Michael Byrne, Newnan, Ga., Suzuki, 88
5. Kevin Windham, Centreville, Miss., Honda, 84
6. Travis Preston, Hesperia, Calif., Honda, 76
7. Ricky Carmichael, Tallahassee, Fla., Suzuki, 69
8. Heath Voss, Mico, Texas, Honda, 69
9. Ivan Tedesco, Murrieta, Calif., Suzuki, 66
10. David Vuillemin, Menifee, Calif., Honda, 62

Amp'd Mobile World Supercross GP Season Standings:
1. James Stewart, Haines City, Fla., Kawasaki, 189
2. Chad Reed, Tampa, Fla., Yamaha, 171
3. Timmy Ferry, Largo, Fla., Kawasaki, 142
4. Ricky Carmichael, Tallahassee, Fla., Suzuki, 116
5. Nicholas Wey, Murrieta, Calif., Honda, 108
6. David Vuillemin, Menifee, Calif., Honda, 101
7. Travis Preston, Hesperia, Calif., Honda, 98
8. Michael Byrne, Newnan, Ga., Suzuki, 96
9. Heath Voss, Mico, Texas, Honda, 95
10. Paul Carpenter, Ithaca, N.Y., Kawasaki, 86

Amp'd Mobile Western Regional AMA Supercross Lites Event Results, Houston:
1. Ryan Villopoto, Poulsbo, Wash., Kawasaki
2. Jason Lawrence, Carlsbad, Calif., Yamaha
3. Josh Grant, Riverside, Calif., Honda
4. Josh Hill, Yoncalla, Ore., Yamaha
5. Martin Davalos, Cairo, Ga., KTM
6. Jake Weimer, Rupert, Idaho, Honda
7. Matt Lemoine, Pilot Point, Texas, Yamaha
8. Kyle Cunningham, Springtown, Texas, Yamaha
9. Chris Gosselaar, Victorville, Calif., Kawasaki
10. Troy Adams, Homosassa, Fla., Suzuki
Amp'd Mobile Western Regional AMA Supercross Lites Season Standings:
1. Ryan Villopoto, Poulsbo, Wash., Kawasaki, 147
2. Jason Lawrence, Carlsbad, Calif., Yamaha, 113
3. Jake Weimer, Rupert, Idaho, Honda, 89
4. Josh Grant, Riverside, Calif., Honda, 84
5. Christopher Gosselaar, Victorville, Calif., Kawasaki, 77
6. Matthew Lemoine, Pilot Point, Texas, Yamaha, 77
7. Josh Hansen, Lake Elsinore, Calif., KTM, 71
8. Josh Hill, Yoncalla, Ore., Yamaha, 70
9. Steve Boniface, Corona, Calif., Kawasaki, 61
10. Troy Adams, Homosassa, Fla., Suzuki, 58