Liverpool great Graeme Souness says Saul Niguez struggled on his Chelsea debut in victory over Aston Villa.
Souness says Villa midfielder John McGinn's performance would keep Saul "awake tonight".
Souness said: "“He (Saul) will look in the mirror when he's cleaning his teeth tonight and it will be McGinn looking back at him.
"He huffed and puffed. In Spain he was playing for a team who won the league out there, Atletico, they would be involved in cup finals most weeks where everyone wants to beat them.
"Over there, I'd imagine the same intensity comes in waves in Spain, our league it's incessant and it's there all the time.
"For a man of his experience, when you're in possession they'll come after you in packs [in Premier League ] on the continent that'll happen occasionally.
"Against a team of a high energy like Villa, it was happening all the time. He was rattled, making passes under no pressure at all and giving it straight to the opposition.
"The very top players learn quicker, I think this will happen to him, this will be a learning curve. That will be a hard 45 minutes for him today, he'll go away. That'll keep him awake tonight."
Need a VPN? Or seeking to switch? Then support Tribal Football by clicking here to sign up with our official partners NordVPN. Not only will you receive the best VPN experience, but also great discounts by signing up via Tribal Football. Thanks for your support!