Yoda is canonically more skilled than Palaptine as per the ROTS script:
YODA unleashes a ferocious assault on PALPATINE, causing him to almost go over the edge. The Dark Lord drops his lightsaber but recovers with a BLAST OF ENERGY from his hands that surrounds YODA. YODA is deflecting the Sith Lord's lightning bolts.
Furnace-heart Anakain beat Dooku far more soundly than Yoda did. Soooo.