Manning Snr has bounced back from his career-threatening injuries to lead his Denver Broncos team to Sunday's Super Bowl - a game which Eli thought he would never watch his brother play in again.
Eli told NFL Network: "I saw him after that neck surgery, and I was pretty much convinced that he was done playing. I felt that there was no way he could come back and play football.
"The first time that we were just throwing a ball in the backyard of our house - 15 yards away - and he couldn't throw it on a line. He wanted to come back and play football, but I didn't think it would happen.
"I remember watching his pre-season game last year and I was worried. I didn't know how it was going to work. But sure enough, he's been able to do it, and even this year, he's been stronger, his arm strength's been stronger, and he's been better than ever. It's been an amazing journey for him and what he's overcome and for me to watch him to go through it, and the dedication to work has been inspiring."
Peyton has just one Super Bowl victory to his name, from his time with the Indianapolis Colts, while Eli has won the biggest prize twice with the Giants since 2008.