With the Demons losing to the Magpies by 53 points in round two and 11 goals on the Queen's Birthday, Bailey said they remained the toughest opponent Melbourne has faced after 16 rounds.
"I have to say Collingwood in both games served it up to us, to be honest," Bailey said when asked post-match if there was a better team than Geelong.
"They were very good on the counter-attack and they've got a number of midfielders who move through the ground.
"St Kilda was a team we struggled to score against in the second half of football, but maybe there is not much between them anymore.
"If you look at win/loss, St Kilda and Geelong are still the two best teams in the competition."
The two losses against the Magpies were Melbourne's worse for the season.
A 55-point loss to the Brisbane Lions in round 13, a 53-point loss to Port Adelaide in round three and a 48-point loss to Essendon in round 12 were next. The Demons went down to the Cats by 43 points in round six.
Melbourne's three wins have come against Richmond, West Coast Eagles and Port Adelaide.