"We can work on tactics and formations but you can't legislate for two player switching off at a set-piece," Dickov said.
"Especially against a big, physical team. You can't expect to come back from that.
"It was far too easy. Far too easy."
Dickov believes a long injury list is starting to bite after a loss that leaves them just a place above the drop zone.
Doncaster were without nine first-team players and most of their preferred defensive line.
"You have to deal with it," said Dickov, who has now seen his side win once in 12 games.
"I've been loathe to blame the injuries in recent weeks but it is taking its toll.
"We want to stay in this division. I still believe we will do that comfortably."