Virgo told BBC Sussex: "It was a good all-round performance from everyone and it was a massive three points."
"We knew the problems that Brentford could cause us and we dealt with it very well from the back. We knew defeat would not help us get up the table."
The midweek win was only their fourth home league victory of the season.
The 27-year-old added: "It was a well documented record that wasn't too good. We knew we had to get a good three points against them.
"When you come this close to the end of the season and points are very, very important, you do have to take it a game at a time."
The victory also saw Glenn Murray's first goal at the Withdean Stadium since the 5-0 victory over Yeovil on 14th March last year.
"He's done very well, always created chances for himself, but unfortunately for some reason here he hasn't scored," Virgo said.
"I'm as delighted as anyone for him to get a home goal. I don't think we ever saw it as a burden on his back."