Mark Bosnich says Manchester United can blow the title race wide open by beating Chelsea at Stamford Bridge.
Jose Mourinho's table-toppers are eight points ahead of United, who sit third, going into Saturday's clash.
But Bosnich insists the Blues have not got the Premier League crown wrapped up just yet and is backing Louis van Gaal's in-form side, chasing a seventh successive win, to put themselves firmly in the hunt for the title.
"Chelsea are coming up against a Manchester United side playing their best football of the season," the former goalkeeper, who played for both sides, told the Alan Brazil Sports Breakfast.
"It would really set a cat amongst the pigeons if Manchester United go to Stamford Bridge and win.
"Let's not forget that season when Manchester City won the title with that extraordinary last minute strike from Sergio Aguero. Six games to go, they were eight points behind Manchester United and came back and won [the title] so stranger things can happen."