Roger Federer declared the main reasons for his success were "grit" and hard graft as he rejected the theory his tennis game was "effortless".

Federer, one of sport's highest achievers, looked to set the record straight as he delivered a graduation speech, external at Dartmouth College in the United States.

The Swiss swapped the shorts he had worn "almost every day for the last 35 years" for a robe that was "hard to move in" as he spoke when receiving a Doctor of Humane Letters degree from the New Hampshire institution.

The 20-time Grand Slam winner, who hung up his professional racquet in 2022, talked about how "awful" he finds the word 'retired'.

He said he had instead "graduated tennis" and, like those he was speaking to, had "finished one big thing" and was "moving on to the next".

The 42-year-old then went on to deliver three "tennis lessons" he had "relied on through this transition", which he identified as:

Federer won Wimbledon eight times and was renowned for the stylish and elegant nature of his game.

"People would say my play was effortless. Most of the time, they meant it as a compliment," he said in Sunday's ceremony. "But it used to frustrate me when they would say, 'He barely broke a sweat', or, 'Is he even trying?'.

"The truth is, I had to work very hard to make it look easy.

"I didn't get where I got on pure talent alone. I got there by trying to outwork my opponents.

"Most of the time, it's not about having a gift. It's about having grit."