Despite Roma adopting a very cautious approach throughout the whole game, Chelsea finally managed to win the tie through the England defender's header on 77 minutes.
The home side controlled possession right from the start, but Roma's resilient defense stood in the way of any real chances.
Surprisingly, the game's first opportunity fell to Roma when Francesco Totti's pass seemed to have cleared Mirko Vucinic before Petr Cech ran off his line to clear.
Three minutes later, Deco laid his free kick to Frank Lampard but the latter's excellent effort from the edge of the box clipped Alexandre Doni's bar and went over.
Roma's defense looked comfortable and The Blues couldn’t convert their domination into goal scoring opportunities.
It all stayed the same after the interval, and on 52 minutes Matteo Brighi had his penalty protests waved away by the referee following a Ricardo Carvalho tackle.
As nerves started to rise, Terry came to Chelsea's rescue when he bravely leapt to meet Lampard's corner with a well placed header past Doni.
After the goal, Chelsea kept on piling the pressure and they could have scored a second if it wasn’t for Doni who brilliantly tipped another Lampard free kick over.
In the same group, Bordeaux managed a tough 1-0 win over visitors CFR Cluj of Romania to put qualification spots up for grabs.
The French side had to count on the assistance of Cluj defender Ricardo Cadu who scored an own goal in the 54th minute.
After three rounds, Chelsea are still top of group A with seven points. Cluj are second with both Roma and Bordeaux are joint bottom with three points each.