Souness has been thrilled by the effect the sale of Coutinho has had on his old side, in particular the fact it allowed them to sign Virgil van Dijk and Alisson from Southampton and Roma respectively.
During an appearance on Sky Sports, the Scot said: “It was wonderful business to sell Coutinho and buy those two, they've taken them on to another level.
“When you think [Loris] Karius, if Alisson plays they might have won it a couple of years ago.
"You don't win any big trophies unless you've got a proper goalkeeper. They now have one and what it does everyone is a bit more confident in the team.
“Liverpool are very dangerous because they don't have to be at their best to win games because they're rock-solid at the back."