Fergie was not happy with the performance of the United defenders during their 3-2 defeat to Inter Milan on Wednesday.
Rio admitted: “Against Inter, we didn’t defend well at all. I don’t know if the manager was talking about individuals when he criticised our display, it was more that as a team we didn’t defend well.
“Playing against someone like Inter raised questions that clearly needed to be answered.
“Those have been addressed and it will show when we play Chelsea.”
He said: “The Inter game was definitely what the doctor ordered.
“We’d been on tour in Asia playing against teams who weren’t really anywhere near the standard of teams we are going to face in the league.
“We got some positives out of it in terms of improving our fitness and we also got back to playing at a quick tempo.
“We probably learned a lot more against Inter than we did in the whole tour of Far East.”
