Villa lost 2-1 to Stoke City on Saturday afternoon.
Stoke beat Villa 2-1 but went two goals up before the visitors would get one back.
Roberts, however, saw no passion or desire from the Villa players after the Potters netted their second - suggesting it was one of the worst goals (or reactions to one) we will ever see.
And the former striker told the BBC: "That was one of the worst goals to concede we are ever going to see.
"Someone get there, someone show some desire. The thing was the reaction of the Villa players. No one showed any aggression or passion, it was just get the ball out of the net and get going."
It's hardly the first time this season Aston Villa's players have been accused of lacking fight. Stoke would have been grateful for it as they stepped off the gas considerably.
Villa did respond better than normal by netting later on but it still wasn't enough on the day - and it has been nowhere near enough all campaign despite plenty of chances to put things right.
Next up for the Midlands outfit is a home clash against Everton on Tuesday night.