Winning (5)
There are a few possibilities for this:
on a roll
'winning' is the definition.
(both can mean in the lead)
This is all the clue.
(Other definitions for ahead that I've seen before include "In the lead, in advance" , "at pole" , "in van" , "In the leading position" , "In the vanguard" .)
(Another definition for ontop that I've seen is " Leading".)
'winning' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for on a roll that I've seen before include "name could be found here?" , "Hitting a purple patch (as bacon might be?)" , "Having a run of good luck (colloq.)" , "Where ham may be" , "Enjoying good luck" .)