This is the first bonus installment of "Deep Reads," the best of The Post's narrative journalism. It's a story about two tennis stars, Chris Evert and Martina Navratilova, who turned a rivalry into an enduring friendship – and cancer support system.Read more:Tennis legends Chris Evert and Martina Navratilova became friends as teenagers but then split apart as each rose to No. 1 in the world. But they grew back together as they forged one of the greatest rivalries in sports and embarked on ambitious lives in retirement. After 50 years, they understood each other like no one else could. So when cancer came, they turned to each other.This story is the first in a collection of new, occasional bonus episodes you’ll be hearing from “Post Reports.”  We’re calling these stories “Deep Reads” and they’re part of The Post’s commitment to immersive and narrative journalism. Today’s story was written by Sally Jenkins of The Washington Post and read by Adrienne Walker for Noa: News Over Audio, an app offering curated audio articles.