The actress's character Tina McIntyre will soon have a dramatic showdown with Terry, which leaves her fighting for her life after she falls and hits her head.
In real life, Pivaro recently returned to screens for a guest stint as Terry after time away from the acting profession.
Keegan told itv.com: "It's been great working with Nigel. I think Nigel's seen as sort of a Corrie icon, so it's always great when you work with people who you grew up watching.
"He's a really good actor as well - he plays the part of Terry really well. You come away from the scene actually hating him, because he's that good!"
Keegan added that she hopes a comeuppance is on the way for Terry, who lies to his son Tommy about the circumstances surrounding Tina's injuries.
She confirmed: "Terry doesn't tell Tommy exactly what happened - he pretends it's a loan shark that threw Tina on the floor and made her bang her head.
"It's not looking great at the minute for all of them. Hopefully Tommy and Tina are going to see Terry for what he really is. But we'll have to wait and see."
Coronation Street continues tonight (May 8) at 9pm on ITV1.