The London club head into the international break six points clear of second-placed Manchester City with a game in hand after Loic Remy came off the bench to score the winner with his first touch 13 minutes from time.
Chelsea were seemingly coasting to victory when impressive finishes from Eden Hazard and Diego Costa put them two goals up after only nine minutes at the KC Stadium on Sunday.
Hull had other ideas, though, and Ahmed Elmohamady pulled a goal back before a howler from Thibaut Courtois gifted Abel Hernandez an equaliser just 74 seconds later.
Remy had the final say after replacing Costa, as Allan McGregor made a hash of trying to keep out his left-foot strike to leave Mourinho optimistic that his side will be crowned champions
He said: "The title race should be over, in normal conditions Chelsea should have eight, 10 or 12 more points than we have but football is unpredictable.
"The reality is that we have a six-point lead, the best situation we've had all season. The maximum distance we had was eight points but at that point we had 20 matches to go.
"At this moment we have a six-point lead with one match in hand, which could help us or not. I'm pretty confident, I believe in my players, I believe we can do it but I know it's difficult."
Costa left the field clutching his hamstring to raise concerns that he could face another spell on the sidelines, but Mourinho believes he has the cover to cope without the Spain striker.
He revealed: "It's a hamstring injury. When a striker is playing, the team needs a goal to win the game and he says it's over for him, it's over.
"He tried to play the Champions League final with Atletico [Madrid] and was injured, he has that fragility, we know his hamstring is not a strong one.
"He works hard in the week to compensate for the weakness he has there but the injury can come. We have Remy and [Didier] Drogba, we never cry about injured players so let's move on."
