Gardner says the big keeperâ€™s progress has been such that he can now be considered â€śworld classâ€ť as the custodian closes in on 100 appearances for the club.
â€śIâ€™ve been so fortunate throughout my career to play alongside some top keepers,â€ť he told safc.com.
Iâ€™ve played with Brad (Freidel) and Joe (Hart) and theyâ€™re great â€“ Simon is in the same category.
â€śPeople say that Joe is the best keeper in the world; I think that Simonâ€™s definitely up there with the best and Iâ€™m sure other people will agree.
â€śHis saves against Arsenal were immense.â€ť