I must have missed it, when was he in their box? The only notable moment I remember is him kicking air in their half after a corner clearance came flying at him, which Aurier hit quite well.
As to the general point, They had Abraham, Werner, Mount, Giroud, Ziyech in our box several times, they didn't need him there. Conversely, as Kane, Son and Bergwijn were providing so much defensive cover, they didn't get into the Chelsea box much. So we did need someone else to pick up the slack in that regard, never really happened, certainly not through Sissoko.