Durge for sure. He was besting Anakin, only 5 months prior to ROTS, for a while, before getting overconfident and getting himself killed. Anakin 5 months before ROTS would have very little trouble with Jango.
Why didn't Durge take part in this mercenary tournament? If he did enter that mercenary tournament, then Durge would have been cloned 1.2 million times and possibly more instead of Jango.