Dutch international Anita, a £6.7m summer signing from Ajax, came through the ranks of the famous Amsterdam club with the 30-year-old.
Anita, 23, said: "I know Pienaar well. I played with him for two years at Ajax.
"He was in the first-team when I made my debut, but we trained together a lot.
"We always had a good laugh but Monday I know it will be quite a battle."