Dooku wasn't in his prime, so although he was stronger, more skilled and more matured in his power, he needed to expend more of it just to remain on a even keel with Anakin than Anakin did. The novel also shows he was actively replenishing himself on Force reserves and relying more heavily on those reserves just to keep fighting. While Anakin just got stronger and stronger. Eventually he was in a position where Anakin could kill him literally just by wanting to.
The same argument could be made for Yoda. He just reached the point were he had no hope of victory by continuing the fight due to simply losing on attrition, which is why he just cuts and runs.