We could see how Roger Federer and Rafael Nadal are big friends last weekend at the Laver Cup tennis event. They encouraged and helped each other, with the goal of bringing the title to Team Europe, which they did. Asked about his relationship with the Mallorcan player, Federer said: 'It changed.

At the beginning he was very shy and respectful with other top 10 players, and especially because I was No. 1. Then as the time went on his personality increased and he started playing his chances. It was interesting to see him growing up until that he became the Champion he is today.

We had hard and painful battles on court, issues as well, but there was always an enormous respect between us. We shared many strong moments on court and off court in a very friendly way. As soon as we grew up, I realized how much Rafa was important in my career.

He will forever be my ultimate opponent. He was the one who helped me to improve the most and to be a better player. And at the same time I say if he didn't exist, I would have not won so much (laughter). Rafa's presence was an extra motivation.' Asked what it meant to him to team up with Rafael Nadal, Federer said: 'We had different feelings than the past.

We were a team, training together. In such situations on the practice court you are almost happy when they beat you because it means they are well-shaped. Usually you do not like to lose but here we trained like a team does. If Rafa or any other player wanted to train at a certain hour, I was okay with it.

These are little things that on the Tour don't happen because you think about yourself, you want to choose your hours and want to win practice session matches. Spending a week like this in group with Rafa and others, almost all of them who are top ten players, was very special.' ALSO READ: Toni Nadal: 'Roger Federer seems eternal, but Rafa will beat his 19 Slams'