in hot pursuit
at someone's heels
on someone's heels
hard on someone's heels
hot on someone's heels

A second and a third followed hard on his heels.

She sat back on her heels and looked at him.

We did a lot of play action and they were on their heels.

You've got the top three players in the world right on your heels.

The Americans, especially, cannot sit back on their heels and hope for a decision.

But I was maybe a little bit back on my heels.

He sat back on his heels to read the last line.

Do you remember the people who sit on their heels?

He sat back on his heels and looked at her.

I was sitting on my heels in front of her.