‘All Greek to

Roger Federer was briefly refused entry to the player’s area, after a stickler of a security guard spotted that the winner of 20 grand slam singles titles was not wearing his accreditation badge. A day later, the great man suffered further indignity, as he found himself summarily ejected from the tournament.

The culprit this time was Greece’s Stefanos Tsitsipas, 20, who produced a masterpiece of classical tennis to curtail Federer’s sequence of 17 straight victories at the Australian Open.

‘‘I am the happiest man on Earth right now, I cannot describe it,’’ an emotional Tsitsipas told John McEnroe in his on-court interview, while clutching his shoulder-length mane in disbelief.

The result was a blow for Federer’s legions of international fans.

But if we are thinking of the future, it is no bad thing that the man to oust him should have been Tsitsipas, a graceful performer whose instinctive volleys and one-handed backhand can only be described as Federeresque.

These two players have never faced each other before in a competitive match but it still felt like the master being surpassed by the apprentice.

Even Federer, 37, said afterwards that he could see a little of himself in his conqueror. ‘‘I guess so. He has a one-handed backhand and I used to have long hair, too. He has a continental grip [and] that’s more my way, let’s say, than Rafa’s [Nadal] way.’’

Physically, Tsitsipas is both explosive and elastic – a combination which soaks up the impact of these rock-hard courts – while his mental game was aweinspiring.

Federer applied huge pressure throughout, but Tsitsipas simply refused to crack, saving all 12 break points that he faced.

Even when British chair umpire James Keothavong hit him with a pair of time violations in the very first game, the second of which cost him a first serve, he managed not to unleash the stream of Greek obscenities which had sullied his third-round victory over Nikoloz Basilashvili.

Meanwhile, Federer’s forehand – the peerless scalpel that has carved out the bulk of his 99 career titles – was losing its edge.

‘‘I have massive regrets,’’ Federer said after his 6-7, 7-6, 7-5, 7-6 defeat. ‘‘I felt like I have to win the second set [and that] cost me the game tonight.

‘‘I also didn’t break him at the Hopman Cup [in a recent exhibition match that Federer