Davydenko, who has reached the quarter-finals at Melbourne Park on four occasions, is currently placed 40th in the world rankings.
Despite Davydenko's lowly position, Federer insists that the 31-year-old is still a difficult opponent.
"It's a tough match up with Nikolay," said Federer following his 6-3 6-4 6-4 win at the Rod Laver Arena.
"He's a good player. It's nice to see him playing well again, he's had some difficulties in the last couple of years.
"It's always a pleasure to play against him whatever his ranking."
Federer has faced Davydenko 18 times in his career, coming out on top on 16 occasions.