Roger Federer crashed out of the US Open in the fourth round after losing in four sets to Australian John Millman.

It was the first time Federer has ever lost to a player outside the top 50 in New York and it was even worse considering he was a set and a break up.

Here, Press Association Sport assess Federer’s form and what it possibly means for his future.

No Need To Overreact

There is no doubt that this was a shocking result for the Swiss maestro, especially considering the position he put himself in, having two set points to lead by two sets to love.

But there is no suggestion that this should be viewed as anything other than a freak result.

The sweltering conditions played a key part in New York and Millman was able to adapt better.

Federer’s overall recent record has not been too bad as he reached the quarter-finals at Wimbledon before getting to the final in the last US Open warm-up tournament in Cincinnati.

He has a 33-5 record for the year, with three titles, including the Australian Open, so he is still one of the best – a Grand Slam and a stint at world number one tells you as much.

Hard To Keep Up 2017 Form

It would be unwise to view this result in anything but isolation, after all, he has not won at Flushing Meadows since 2008, so it is hardly a stronghold for him.

Federer’s problem is that he was so brilliant in 2017 that his record this year, although still impressive, is modest in comparison.

With Rafael Nadal and Novak Djokovic now back to their best, Federer is not finding it as easy to win the big tournaments.

Don't Rule Him Out

Yes. Most people had begun writing the obituaries of a brilliant career when Federer was left in a heap on Centre Court in 2016 with a knee injury hampering him in his Wimbledon semi-final against Milos Raonic.

The Swiss took the rest of the year off to recover and everyone thought that was that. And how wrong they were as in his mid-30s he came back and played arguably the best tennis of his career on the way to the Australian Open and Wimbledon titles, claiming the ‘Sunshine Double’ in Indian Wells and Miami and returning to world number one.

Only a fool would consider him done after this set-back.

More Time Off

At 37, it is obvious to say that Federer is in the twilight of his career, but he is doing his best to prolong it.

Since his injury-ruined 2016, the Swiss has carefully managed his schedule and he will continue to do that.

He is unlikely to ever play on clay again in order to target the grass-court and US hard-court swings.

As time ticks on, he may reduce his diary even further, perhaps skipping either the Asian or the European indoor tournaments at the end of the year in order to be in better shape for the Australian Open.

Whether the stop-start nature becomes more difficult as he approaches his 40th birthday remains to be seen, but as long as he feels he can win the top tournaments, he is likely to continue.

Conditions Played Its Part

Unsurprisingly, Federer is not viewing this as a catastrophic result and pointed to his inability to cope with the conditions as the main reason for the loss.

He said: “I wish I could have led two sets to love and then maybe the match would be different and I would find a way. It was just tough. I thought John played a great match in difficult conditions. I’m happy I’m getting a rest now. Then I come back for the Laver Cup and hopefully finish the year strong.”