@larkim – pretty much it but these guys recover pretty quickly and depending on where the domestiques get away and where the GC contender attacks they might be aided by the terrain – hills, descents, twisty or narrow roads. Sometimes luck plays a part.
After that it depends on who’s willing to help the leader’s team, if no-one has a vested interest in doing so then they’ve got to do all the work themselves and at this stage in the race the leader might only have two or three domestiques in the lead group with him so rather than three riders vs the peloton or at least a big bunch it becomes three riders vs three or four. Much more favourable odds.
Edit: as if to prove my point about Sagan – having got the intermediate points he’s now eased up as he knows he’s unlikely to keep pace with the hill specialists.