Here's when Roger Federer will start his 2018 tennis season

Swiss great Roger Federer will use the Hopman Cup in Perth as preparation for the defence of his Australian Open title in 2018, mirroring his successful early season build-up this year.

The 18-time Grand Slam champion made his long-awaited comeback after six months out with a knee injury at the mixed teams tournament in January, and it served him well.

Against the odds, he went on to defeat old rival Rafael Nadal in a thrilling five-set final at the Australian Open, and followed it up with titles at Miami, Indian Wells and on grass at Halle two days ago.

Federer, who will again team up with compatriot Belinda Bencic, attributed his Australian Open success in part to having such a good time in Perth.

"I'm very happy to be coming back (to the Hopman Cup) because I had the best time on and off the court," said the world number five in a statement issued by tournament organisers.

"The fans were absolutely amazing, there were I think about 6,000 people at my first practice which I couldn't believe, it was almost surreal walking into the stadium."

Outside the court, the Federer family visited tourist attractions and joined surf lifesavers for an impromptu beach tennis match at Cottesloe Beach.

"Off-court we had a tonne of activities. My family and I had the best time. It was just a great, relaxing start to the year," he said. "Plus I played some really good tennis and I can't wait to play again in Perth."

Bencic was also excited about returning.

"The Hopman Cup was amazing for me earlier this year," she said. "Playing with Roger was obviously a dream come true and I learned so much from him during that week on and off court."

France won the 2017 Hopman Cup, beating the United States in the final.