Henderson assisted Sadio Mane's opener in the 2-0 win.
Souness said on Sky Sports: "He's got great energy, he's box-to-box and he's now off the leash and he'll be better for it.
"It's definitely his best position. Jordan wants to be on the ball, involved and he's got that athleticism.
"To play as an anchor man you have to be extremely disciplined and a lot of the time you're attracted to the ball but can't go there. I think he's not suited to that role at this moment in time."