The Blues, back under the guidance of former boss Mourinho since the summer, beat Liverpool 2-1 on Sunday to move two points behind Premier League leaders Arsenal at the halfway stage.
And after two terms where they have struggled to remain in contention - finishing 25 and 14 points behind respective champions Manchester City and Manchester United in 2012 and 2013 - Terry has tipped them for another title tilt.
"The last couple of years we've lost our identity a little bit," Terry told Chelsea TV.
"There's some good teams in the league and when you go 3-2 up (for example) it's important you get men behind the ball and dig in deep and not give them opportunities to really feed on. I think we're doing that really well at the moment.
"At times when we're looking really solid, getting the wide men in and then when we do break it's important for them to then go again and show their fresh legs going forward."
Eden Hazard scored his eighth Premier League goal of the season before Samuel Eto'o poked in the winner against Liverpool and Terry reckons the Belgian has become the "complete player" under Mourinho.
"It's important you keep it tight at the back and you look for those type of players to create something or do something out of nothing," Terry added.
"He's been doing that all season (and) scoring. The last four or five games he's been really tracking back and really dug in.
"He's really dug in and added that to his game and made him the complete player."