By Lewis Franck
Patrick, who is racing in some of NASCAR's second-tier series when her IndyCar schedule allows, started 36th in the 300-mile race but dropped toward the rear of the 43-car field. She twice was penalized for speeding off pit row.
Her NASCAR debut last week at Daytona International Speedway was ended by a multi-car crash about halfway through the race.
"I've gotten used to running up front," said Patrick, the only woman so far to win an IndyCar race. "It's an adjustment... It's like starting from zero again."
Busch held off Greg Biffle for the victory. Both drive on NASCAR's top tier Sprint Cup Series.
(Editing by Gene Cherry and Greg Stutchbury)