Watch AZ vs Heerenveen Live Streaming
Watch AZ vs Heerenveen Live StreamingIn their last two encounters two 94th-minute winners gave Chelsea the edge and that, says the midfielder, gives them encouragement.
"The good thing is that every time we play a big game, everyone is up for it," he added.
"Nothing is impossible. We have been playing so many games where people write us completely out, but that gives us more motivation to disappoint those people.
"We believe that on our day we can beat anybody."
Diao hopes to be able to earn himself another 12-month contract at the Britannia Stadium this summer but much will depend on his level of fitness.
"I don't want to retire just yet," he told The Sentinel.
"Although I am 33, I have missed a lot of games over the years and so I haven't got the mileage in my legs but I still win my tackles in training."
