The England international spoke about his improving understanding with his Brazilian team-mate and cannot believe the turnaround at Stamford Bridge since Di Matteo's arrival
The 26-year-old, who joined the Blues in January, has made 18 appearances for the club and featured in Chelsea’s semi-final wins against Tottenham in the FA Cup and Barcelona in the Champions League.
And the ex-Bolton player is now starting to gain a better understanding with his Brazilian team-mate.
"I'm still bedding in and getting to know the players, but I've got to know the likes of David Luiz pretty well who's a great character, and also the younger lads like Ryan Bertrand," he told Chelsea TV.
"The more you play with someone the more you get to know their game.
"I think our relationship will grow, [David Luiz] is a fantastic player and since I've been here he's been brilliant, knowing his game more than I did before I joined obviously helps, as it does with him knowing mine better."
Cahill, however, revealed his disappointment at being forced off through injury on Tuesday night during his side’s Champions League semi-final second leg away at Barcelona. The England international picked up a hamstring injury in the opening 15 minutes and it was feared his season could be cut short, but he believes he will be back sooner than expected.
He stated: "It's not too bad. I was so disappointed as it came so early in game.
"I couldn't believe my luck. I got a small tear and I felt it go on the night, but it could be worse and I'll be back as quickly as possible."
The former Aston Villa player arrived in the days of Andre Villas-Boas and has been part of a remarkable turnaround since interim coach Roberto Di Matteo took over from the Portuguese.
And the centre-back cannot believe the Italian’s impact as well as his own performances considering he was at Bolton a few months ago, a team now struggling against relegation.
He added: "The confidence and spirit's been really good, since he took the job everything he's touched has turned to gold.
"He's used the squad fantastically well and he's picked the right teams for certain games and we've got the results. Everyone wants to play in the big games but it can't always be the case.
"A big part of management is to speak to the players and let them know the situation, which he does really well.
"It's absolutely crazy, for someone like me who at one stage of the season was at the bottom of the league, to come here and go so far in these competitions, people say it's a dream come true and it is."