The FourFourTwo Preview: Sunderland vs Chelsea
Chelsea have won their last eight top-flight games at Sunderland, and there will be no room for sentiment when they come up against former Stamford Bridge favourite Gus Poyet's struggling side this time around.
The London club moved up to second place in the Premier League with a 3-1 victory over Southampton on Sunday, and manager Mourinho believes they are showing signs that a title challenge is possible.
Jay Rodriguez gave Southampton the lead after just 13 seconds at Stamford Bridge, but Chelsea fought back with second-half goals from Gary Cahill, John Terry and Demba Ba to cut the gap to leaders Arsenal to four points.
Cahill's goal was his first in 2013, while captain Terry marked his 400th Premier League appearance for the club with his second goal of the season.
Mourinho's charges face three of the bottom five in their next three games, but the former Real Madrid coach will not be taking them lightly.
He said: "We now have two matches away (Sunderland and Stoke City) and then Crystal Palace at home, we are playing three teams who need points because of the position they are in, so we will have three very difficult matches."
Brazil midfielder Oscar limped off late in the first half against Southampton after going over on his ankle, so his fitness will be monitored ahead of the trip to Wearside.
David Luiz (knee) may not be ready to return, while Samuel Eto'o (muscle strain) is set to miss out once again and Marco van Ginkel (knee) is a long-term absentee.
Sunderland claimed only their second away point of the season when they held Aston Villa to a goalless draw on Saturday.
Poyet, a cult figure at Chelsea during his playing days, has brought an air of optimism since he was appointed as Paolo Di Canio's successor in October.
Sunderland have won all three home games since Poyet arrived, and the Uruguayan will be determined to continue that run against his former club.
Skipper John O'Shea (groin) and goalkeeper Keiren Westwood (shoulder) are injury doubts, while defender Carlos Cuellar (hip) is definitely out.