"They are both great sides on their day, but maybe they don't win enough games when they don't play well.
"Both are improving though, and they'll push us all the way this season."
Cole was surprised inexperienced Arsenal were title contenders for two thirds of the season, and added: "It did surprise me. The way they started was incredible.
"But people were talking about them like they were the Harlem Globetrotters.
But if you're an experienced football man you're thinking: 'Hold on, there's a long way to go'. They got tired and their inexperience showed towards the end of the season.
"This season, with a bigger squad and more experience, they'll be stronger.
"Obviously Cesc Fabregas is their top player, but I was really impressed with the way Theo Walcott finished the season.
"If people aren't demanding him to be in the England team, they're writing him off.
"But I think he'll develop into a world-class player if people just give him some space to express himself."