Fabregas has worked under both Mourinho and Pep Guardiola and the two are often seen to be polar opposites, despite their repeated clashes.
But the 27-year-old insists the two are both driven by the same intense will to win, and claims they are in fact remarkably similar.
He told El Pais: "Don't be so sure [that they're so different]. I think they have one very important thing in common: they're winners.
"They both hate losing. They're more similar than many people think. Mourinho is asking us to play attractive football. This [Chelsea] team aren't about sitting back: we're about attacking and getting on the ball.
"They're both winners and they both like playing attractive football, though their working methods aren't exactly the same - they have different ways of going about things."
The Spain international played for Barca at a time when they were in fierce competition with Mourinho’s Real Madrid, and he concedes that he would never have envisaged himself playing under the Portuguese back in 2012.
“Three years ago, no," he said when asked if he ever expected to work with Mourinho. "It just shows you how you can never tell in life, and even more so in football.
"We had a very intense rivalry with Mourinho. It never reached the level of hatred, not even close, but there were disagreements with him and [John] Terry too. Chelsea were always the team that I most wanted to beat."
