Schalke currently sit 2nd in Group G, 3 points behind Tuesday's opponents. However, a poor loss to Sporting Lisbon last time out has dented their hopes of progressing to the next round of the competition. They need a positive result against Chelsea to keep their European hopes alive.
Chelsea have 8 points from their opening 4 Champions League games. Despite topping Group G, Mourinho will have been disappointed at their European campaign so far and will demand a win here in order to guarantee their place as group winners in Germany.
Di Matteo will look to get one over his former employers, but Chelsea have too much about them and should secure victory here.
Team News
Schalke 04
Roberto Di Matteo will be without Sead Kolasinac, Jefferson Farfan and Julian Draxler for the welcome of Chelsea.
The Italian may also be without Fabian Giefer, Leon Goretzka, Chinedu Obasi and Sidney Sam.
However, Obasi is expected to be passed fit and should start on the wing.
Chelsea
Jose Mourinho has a clean bill of health for the trip to Schalke.
The Portuguese must decide whether to start Thibaut Courtois or Petr Cech in between the sticks, though it's the Belgian who is tipped to feature.
Diego Costa will likely lead the attack.