It is stated in Rin no Sho that the Sannin are inferior to Hiruzen.
"伝説の三忍●かつて木ノ葉隠れ の里で、火影に迫る強さを誇っ た三人の忍者を指す。自来也と 大蛇丸はその内の一人である。
Sannin: Three ninjas who once boasted strength approaching that of the Hokage in the Hidden Leaf Village. Jiraiya and Orochimaru were among them."
Old Hiruzen had the power to counter All is Suffering, which I would say puts him into contention to crack Madara's Susanoo ribcage, sure.
He was also able to disarm Orochimaru and was probably going to have killed him if he did not fight three versus one against him and the other two Hokage, and even then he managed to almost nearly kill him.
Orochimaru, of course, is on the same level of Tsunade as a Sannin, and Hiruzen nearly beat him despite these unfavourable conditions.