Mark Phillips had cancelled out Michael Rose's first-half opener within minutes of the restart but a Bobby Grant brace and an Ashley Grimes finish put the result beyond Southend's reach. Barry Corr, who squandered several chances and hit the post with a header, netted a late consolation.
"We got a lesson on how to play football on a surface that wasn't conducive to playing good football," said Brown.
"Rochdale are renowned for being a good footballing team, but for 90 minutes they did nothing but turn our two centre-halves to face their own goalkeeper, they put balls in behind us and turned us all day. Consequently they played in the right areas of the pitch. We didn't - we tried to play in the wrong areas and we got caught out.
"I felt it was harsh to go in one down at the break, we got ourselves back into it but then basic individual errors after that have cost us dearly. I have a striker, Barry Corr, who could quite easily have walked away with the match ball - but we still wouldn't have won the game.
"If you cannot defend properly and you cannot play football in the right areas you are going to get beaten. Margins in football are fine, but if you don't get the basics right you are going to lose games.
"I have defenders who thought they had a good game because they kept possession and played football. It's not about possession, it's about sticking your head in, kicking it as far as you can on a surface like this and getting your strikers to hold the ball up so the midfield can support them. We didn't do that all night."
It was Rochdale's third consecutive win and saw them go level with their opponents on 57 points.
"I am delighted with that performance," said manager Keith Hill. "It was always going to be difficult to recreate what we produced at Fleetwood where we won 3-0 on Saturday, but we went somewhere near. I was really disappointed with the two goals we conceded, especially the timing of their first goal.
"But we responded really well and the goal that took us into the lead at 2-1 came from a brilliant piece of individual skill by George Donnelly, and that has won us the match. The confidence was there, the energy and the commitment. It was what I expect and I think it's what the players are coming to expect."
- Sports & Recreation
- Barry Corr