De Villiers, who names his Test team today, believes the side that faced the Sharks contained at least 11 of the Test team.
"That was almost their Test side bar one or two changes. We all know it, McGeechan knows it, you know it, everyone knows it," said De Villiers.
"I think their headache will be at wing and at loose forward. They don't really know who to select there, otherwise it's self-explanatory."
"They have a come a long way. I don't sleep very easy looking at them and how they have progressed up till now - they have very good structure to their game."
The Springbok coach also singled out Lions captain Paul O'Connell for special praise - having earlier not rated him as a leader.
"I made one big mistake early in the tour by not rating O'Connell as a great leader. He has showed us that McGeechan made the right decision in choosing him," said De Villiers.
"He is inspirational and you can see everyone around him plays twice as hard when he's in the game. If he's not there you can see there's a bit of a lack of enthusiasm.
"His work rate is also impressive. The man is everywhere, so now I know why McGeechan opted to go for him.
"The way they stand up together as a team tells you there is feeling and warmth there. The whole team is really together, whether it's the Saturday or Wednesday team.
"As McGeechan says, anyone of his squad can play in the Test, they are great rugby players. The reason I say O'Connell has impressed me is that I didn't know him as a leader - that's what's impressed me a lot, work rate and all-round leadership.
"If you can tell me about any weakness in this team, I'd love to hear it. They are well structured and have spent a lot of time on detail. They know what they're doing and when and how to do it."