Former Dagger Gavin Tomlin bagged a fine double and midfielder Kevan Hurst also netted as the visitors stretched their impressive unbeaten run to 14 matches in all competitions.
Still said: "Southend were more experienced, they never allowed us to get going.
"Unfortunately we didn't have enough good players. Not enough people played well.
"In the second half we were better. I thought we had four or five reasonable goalscoring opportunities, but need to score one to get the game changed. We didn't, so fair play to them.
"It was probably one of those games where we just didn't get started. I said at half-time that I could have changed all 11 players.
"It was one those days which wasn't good enough for us, but it's one of the things that I accept because we've not got a lot of experience in our side.
"I just felt all over the pitch they had good players, good knowledge and good experience. They're a good side."