Antonio Conte's men cast the visiting minnows aside at Stamford Bridge in a convincing display that included first Chelsea goals for Davide Zappacosta and Tiemoue Bakayoko on Tuesday.
And after missing out on European action last season, Fabregas was relieved to be back on form in the competition.
"We have been waiting for a long time to be back playing in the Champions League," he told BT. "Finally it arrived. It was a good performance and a good result.
"You never know if these goals can count [for something] at the end of the group stage. We just have to keep going now."
But Fabregas conceded that Chelsea will take some time familiarising themselves with the busy schedule again.
"We just have to take it game by game now," he continued. "We are focused on Arsenal - a tough, tough game - on Sunday. It's a very difficult period for us.
"You can see that the coach rotated five players. We have seven games in 21 days - that's not what we are used to after last year. The Champions League is a competition that last year wasn't there.
"As the coaches say, we have to eat well, sleep well and recover for Sunday."
Michy Batshuayi, who netted the fifth goal, added: "It is good for me and it is good for the team.
"It's my first game in the Champions League."