"I touched the ball and got up and tried to carry on playing, but the referee gave the penalty and we had to get on with it."
To the delight of United's vocal support, De Rossi (the only Roma player to score in last season's 7-1 rout at Old Trafford) sent his kick high over the bar and into the Stretford End.
"If that penalty had gone in it would have made it a lot more difficult for us," Brown said.
"But all in all I think we played well and passed well. We deserved the win."
On facing Barcelona in the Champions League semis, Brown added: "Barcelona will be a difficult challenge but we're playing well as a team and I can't wait for those two games. A lot of the injured players are coming back now and the squad's in great shape.
"Last season [we played AC Milan in the semi-final] with loads of players out but now everyone's back and enjoying their football.
"I was in the 1999 squad for the final but unfortunately I didn't play. It would mean everything to get to a final and play."