The authors prove that the \(Q\)-polynomial association scheme \(\mathcal{W}\) on the blocks of the Witt \(4\)-\((11,5,1)\) design is unique up to isomorphism. This was the smallest primitive 3-class \(Q\)-polynomial association scheme for which uniqueness had not yet been determined. The proof uses the fact that the spherical representation of the scheme onto its first eigenspace holds all the information to determine the scheme up to isomorphism. It thus suffices to show that the corresponding Gram matrix is unique up to orthogonal transformation. The authors do so by considering an association scheme with the same parameters as \(\mathcal{W}\) and deriving some local information. Then they show, partially aided by the computer, that the rest of the scheme can be built from it in a unique way, hence proving uniqueness.