Del Piero used to track back many times, specially when losing ball trying to dribble.
I agree though, Del Piero and Zidane used to dribble and pull tricks at the right moment in the most suitable situation most of the times.
Whereas Ronaldo, Robinho, Neymar etc for instance, they look for it, they put themselves in a position where they have to dribble whereas Del Piero was pulling them out of no where in a classy way.