The Chelsea manager has praised Brendan Rodgers' achievements this season but points out that regularly playing midweek European fixtures is detrimental to their rivals.
The Blues currently sit third following a 1-0 victory over Swansea City on Thursday, one point clear of Liverpool which lost 2-1 at Manchester City.
However, as Mourinho prepares his charges to face Liverpool on Sunday, he feels the time afforded to Brendan Rodgers by a European absence could play a part in deciding the destination of the Premier League trophy.
"Everybody knows that, in this moment, Chelsea, Liverpool, Arsenal and Manchester City are the top four," he told reporters. "So when there is a match between two of them, there is a lot of points you can get. [Rodgers] is doing fantastic, but he is training every week in a calm way, every day, maybe twice a day, which is a big, big, big advantage.
"He needs to work well, because you can work a lot and work bad. The credit is, he works well, but he has a big advantage compared to other teams. Not being in European competition gives them an advantage, not in terms of resting but in terms of working. They can work. These players here [at Chelsea] are going to play 60 matches, Liverpool players are going to play 40 matches. It is a big difference."
Mourinho was quick to play down the rivalry between the sides that ignited during his previous spell in charge of the London club, with long-time rival Rafael Benitez in the opposite dugout. With a colleague from his initial Chelsea reign in the shape of Rodgers now his adversary, Mourinho expects a friendly atmosphere.
"The manager is one of my best friends in the game so there is no rivalry," he added. "And I have full respect for a team with a history like Liverpool."