Barcelona won the Champions League after beating Manchester United 3-1 in the final at Wembley.
Mascherano left Anfield for Barcelona last summer.
Mascherano said: “We are really happy because we have beaten a fantastic team in Manchester United.
“We are delighted to have played the way we like to play so it’s really good for us. We try to play with having possession all the time and trying to play most of the game in the opposite half, playing well and we did that.
“We had a lot of chances to score. We couldn’t quite score all of the opportunities we created in the first half, but in the second half when we had the chances we took them.
“To win the Champions League for any footballer is the top title. Playing at centre-back has been a little bit of a strange situation for me because the last two-and-a-half months I have found myself playing there.
“It’s a position that is not my natural position but I try to do my best and give my best to the team and I’m happy because we reached our target.
“I know Liverpool supporters after my exit were maybe a little bit sad with me, but I’d like to say this victory is for them as well.”
Barcelona lifted the European Cup for the fourth time after goals from Pedro, Lionel Messi and David Villa.
England international Wayne Rooney had earlier equalised for Manchester United in a thrilling match in London on Saturday evening.
