Fabregas and Emmanuel Adebayor struck late on as the Gunners overcame the Italians 2-0 at the San Siro to progress to the last eight.
Fabregas told ITV4: "This is a dream come true. To win in Milan 2-0, it is amazing.
"William (Gallas) said before the game enjoy the atmosphere. That is what we did.
"But this is just the beginning. We are now in the quarter-finals but we have not done anything. It is just one more step."
Captain Gallas was full of praise for his team-mates.
The Frenchman said: "We said we have to show how good we are, how we can play.
"We had to give the maximum and we did a good job. I am proud of the players."