The Latics registered their fourth win in five matches with a comprehensive win over the U's, who have now lost six of their last seven games.
The Latics took a 33rd-minute lead through Jean-Yves M'Voto, who headed powerfully in off the woodwork from Lee Croft's corner.
James Wesolowski drilled wide before Oldham went further ahead just after the hour when Derbyshire's shot was saved by Cousins and the ball bobbled in off U's defender Brian Wilson, after Croft's pass had dissected the U's defence.
Dickov said: "I thought that we deserved the points and at times, our attacking play was devastating.
"We could have scored more and we would have done had it not been for their goalkeeper, who had a really good performance.
"We could have gone in at half-time three or four-up but we knew that the second goal was always going to be important. We got that and we created chances to score more after that.
"I thought that our front four were at times unplayable and they couldn't cope with that. My only slight criticism was that at 2-0, we stopped doing the things that we'd been doing before that.
"But apart from that 10 minutes, for an away performance it was fantastic. We need to keep our feet on the ground and we have a tough game against Swindon next week.
"But if we perform like we did over the last few games, we're capable of winning."