Carmichael and his only real rival, Kawasaki's James Stewart, staged another thrilling performance as the two quickly separated themselves from the pack. And it was Stewart that got the best of Carmichael in the first moto, when the Suzuki star steered off track in the closing stages.
In moto two, Carmichael struggled from a bad start but once again found himself behind Stewart as they sprinted through the field. With Stewart out front, the roles were reversed when James tipped over during the apex of the battle. That mistake allowed Carmichael to ride away with both the moto win and overall.
"I didn't get the best start in either moto," said Carmichael. "And in the second moto, I had to pass a lot of riders on the first lap, which put me in position for the rest of the race. I put my head down and got behind James but I was unable to do anything. Unfortunately, James had some bad luck and fell down. That allowed me to move into the lead."
RC has now won all five of the opening rounds of the 2007 AMA Toyota Motocross Championship Presented by FMF, but will now - as previously announced - step away from the series before returning later in the season to try and take win number 150 before hanging up his boots for a full-time career in stock car racing.
Meanwhile, in the Motocross Lites class, reigning champion Ryan Villopoto picked up his second consecutive win of the season after a weekend in which team-mate and title rival Ben Townley was hospitalised after complaining of nausea and stomach cramps, which may have been an allergic reaction to anti-nausea medication administered by medical staff at the Red Bud circuit.
'BT' was later released from hospital around midnight on Saturday and given the green light to race after thorough medical examinations ruled out suspected appendicitis or any other medical illness.
Villopoto walked away with the first moto, ahead of Townley, but needed half of the second moto to get around the former world champion and earn the overall moto sweep. Honda's Josh Grant was third overall (4-3).
"I have won the last four motos," said Villopoto. "We [Townley and Villopoto] are both going to be battling for the win next weekend in Unadilla."
"Saturday was a tough ordeal but I don't really think it had any effect on today's racing," admitted Townley. "I got two good starts and was second behind Ryan in the first moto but he managed to gap me again. I tried to close him down towards the end but it was too little too late. I was happier with moto two. We had an awesome race and I felt really good on the Red Bud track - it was so much fun and I haven't raced on circuit like that in a long time. I even started doing 'Larocco's Leap' in the second moto which is just wide open on a 250F."
Villopoto now holds a 20 point lead over Townley heading to the infamous Unadilla circuit in New Berlin, NY for round 6 of the 12 round series.