Without enough practice, he does not have a prayer of winning.
not have a prayer
idiomTo have no chance or possibility, usually in the face of peril or adversity.
Origin
disputed originImplies that not even divine intervention could save the person.
The team was so exhausted by the final quarter that they did not have a prayer of catching up to their opponents.
Given the severity of the storm and the lack of proper equipment, the small vessel did not have a prayer of reaching the harbor safely.