Referee Mike Dean pointed to the spot and Jimmy Floyd Hasselbaink sent Freidel the wrong way to level the scores and deny Rovers three points.
"The penalty was very harsh. There was no way it was a penalty. But we have come here and deserved a draw," said Souness.
"No team is going to come here and not be under pressure but we defended well. We were playing against a very good team but we limited their chances."
Souness added: "Andy Cole has been outstanding. He had a lean time by his standards last season with 11 goals but he has got the bit between his teeth now."