The Sebastopol coach, who was a two-time premiership player with the Eagles in the early 1990s, believes the current crop is yet to prove itself in the football heartland.

"They really do need to win over here first if they want to play in the big finals," Lewis said.

The 215-game West Coast Eagle said he has been impressed with his former side, which has stormed to the top of the AFL ladder and been compared to the champion Michael Malthouse-led outfit.

"They're the form side and the hardest to beat in the competition at the moment," Lewis said.

"But it's only about half way through the season. It's too early to say how they will go."

Fifteenth-placed Collingwood brought about the Eagles' only loss two weeks ago.

The Magpies caused the upset at the MCG, casting further doubt about the ability of the Eagles to perform in Victoria.

Lewis said the Eagles would have to finish the home-and-away fixture in the top two to be a chance to make the grand final.

"If they win their first home final and get another at Subiaco the week after, I think they will get to where they want to go," he said.

"If they manage to get those home finals then they're a real big chance."