The Hammers travel to Stamford Bridge as massive underdogs to get the three points against the current Premier League leaders and Song is under no illusions as to how tough it will be.
"They attack together, they defender together," he said to Sky Sports. "At the moment I would say Chelsea would win the league. When I see they way they are playing, they are a very strong team."
Chelsea have still only been beaten once this season - by Newcastle United - and they have impressed all watchers with the style of their victories.
The Blues have rarely looked threatened, with their power and creativity proving too much for most sides to handle.
West Ham, though, have performed above expectations themselves this season and already proven that they can be a match for the best.
The Hammers have picked up wins over Manchester City and Liverpool and they head to Stamford Bridge full of confidence after their impressive start.
Sam Allardyce's men are currently in fourth position in the table and if they are able to pick up any sort of result against Chelsea it would confirm their credentials as Champions League contenders this season.