The former Blue helped the side to their greatest ever achievement, beating Bayern Munich in their own stadium to become champions of Europe for the first time.
Extracts from his recent autobiography, Suddenly A Footballer, touch on his very successful time in West London, including how Di Matteo summoned the players to the team meeting room for one final tactical briefing before leaving for the Allianz Arena.
"A message of courage and passion that we would never forget"
Instead of using the time to cover the strengths and weaknesses of the opposition, Di Matteo took the opportunity to strengthen his squad's resolve one last time.
"There were 25 guys all silent, looking at the big screen in front of us," Mata recalls.
"Suddenly, starting with the goalkeepers and featuring every single player in the team, our families and friends were sending us a message of courage and passion that we would never forget.
"Wives, partners, mums, daughters and sons, fathers and grandparents.
"I still get goosebumps thinking about it.
The effect it had on us was electrifying.
It was Roberto’s idea.
He considered that part of the game crucial, and he was right in every respect, in what he showed us, as well as in the timing.
He was spot-on."
"Think about where you are and how wonderful it is to be there"
Despite being the only Chelsea player to miss from the spot in the penalty shootout, Mata was pivotal to the Blues' historic victory.
It was his perfect delivery from the corner that found the head of Didier Drogba, to equalise two minutes from the 90 and send the game to extra time.
The midfielder recalls talking to his sister beforehand and heeding her instruction to "enjoy the moment" from the second he stepped out onto the pitch.
"Her last words ahead of the final were something like: ‘Take in everything around you, the lights, the sounds, feel the grass.
"Try to stop for a moment to think about where you are and how wonderful it is to be there before the game kicks off.
"So there I was, surrounded by 75,000 people, smelling grass and closing my eyes, seconds before starting the Champions League final.
"If you watch that game back, and look for me just before the referee blows the whistle, you will probably be able to see the grass on my hands."
"The best thing you can do is adapt"
Chelsea went into the final as heavy underdogs and only managed 9 shots throughout the game, in comparison to Bayern's 35.
However, Mata puts their success down to effective containment of the opposition and striking when the moment arose.
"When you play against opponents like Barcelona in the semi-final, or Bayern in the final, the best thing you can do is adapt your team in order to find the best route to victory," he continues.
"We had to play compact and take our chances, and that’s what we did.
"We were aware of our own limits and so we tried to play to our strengths."