Clue: Sure about supporting football club during no-score draw? Yes, sure (2,6)
Answer: OF COURSE
Explanation: Definition: Yes, sure
A charade of OFCO, an envelope ('during') of F.C. ('football club') in 0-0 ('no-score draw') plus URSE, an anagram ('about') of 'sure' (the first one); 'supporting' indicates the order of the particles in the down light.