Federer's incredible praise for 'super impressive' Nadal

Roger Federer is delighted and a little surprised to see Rafael Nadal back at World No.1 after both men spent lengthy spells out of action due to injury last year.

Federer called time on his 2016 season after Wimbledon due to a knee problem, forcing him to miss the US Open and the Olympics.

Nadal then ended his year in October as he sought to recover from a wrist problem, but the two modern greats of the sport returned strongly in 2017.

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They contested a nostalgic final at the Australian Open in January, a match won by Federer, who also triumphed at Wimbledon.

Nadal meanwhile reasserted his familiar dominance on the clay of Roland Garros, later adding the US Open to his 10th French Open crown in a throwback year for men's tennis.

It is Nadal who has climbed to the top of the ATP rankings in the absence of injured pair Andy Murray and Novak Djokovic, leaving Federer, speaking ahead of the new Laver Cup, to express his admiration for the achievement of his long-term rival.

He said: "Am I surprised that he's World No.1 right now? Maybe a little bit, just because last year we were... both injured, not knowing where our careers were going to go, but I'm not surprised that he came back and won the French Open and the US Open.

"Being No.1 is a whole different story. For that we had to see how Murray was going to play and Djokovic was going to have a word to say also, so we didn't know that they were going to get hurt and have bad seasons. But it's super impressive and I'm very happy for him."

Federer hopes Team Europe can ride on Nadal's coat-tails to claim victory at the inaugural Laver Cup in Prague this weekend.

The year's two grand slam winners are the star names for the team event over the next three days as tennis looks to replicate the rivalry of golf's Ryder Cup.

Federer will sit out the opening day of competition in the Czech capital, but Nadal is in action in the sole doubles match.

And the Swiss thinks his long-time rival's sensational 2017 – which has seen him win the French Open and the US Open – can be the perfect inspiration in the clash with the World Team.

"It was a dream season for [Nadal] to win the French," Federer told a media conference.

"Now with the US Open he's got all the confidence and that will serve us well.

"Hopefully the European fans will understand that we're playing in their home will really get behind us."

The opening matches will see Marin Cilic open up against Frances Tiafoe, with Dominic Thiem facing John Isner and Alexander Zverev going head-to-head with Denis Shapovalov.

The first day will be closed out with Nadal partnering Tomas Berdych in a doubles rubber against Nick Kyrgios and Jack Sock.