A late goal from Andy Cole was just enough to secure Rovers a point against Southampton at St Mary's and Souness knows that his side were lucky not to come home the losers.
Saturday's performance was, according to Souness, the worst he's seen during his time at Ewood Park. He went on to blast his players after the game insisting that - should they wish the beat Celtic on Thursday - they will have to improve a great deal from the performance shown at the weekend.
A loss against Celtic will stop Rovers from making any progress to the next round of the Uefa Cup.
Souness said: "We didn't deserve anything from the game but got the goal. That is football, because the other week we went to Celtic, played really well but took nothing from the game. But I felt like wearing a mask after taking a point on Saturday.
"I can't guarantee we won't play as badly again but what I will be telling my players is that if we are as bad as that on Thursday then we're out of the Uefa Cup.
"What I said to them at half-time on Saturday is not worth repeating. It was easily our worst performance of the season," he continued...
"We didn't have any players who were prepared to battle or to take an elbow across their face."
Rovers will be boosted by the return of Damien Duff, Garry Flitcroft and Nils-Eric Johansson for the clash against the Hoops.