Have we seen the last of Roger Federer?
Nothing is certain - and there is always a chance of a 2020 encore - but has Roger Federer graced the Australian Open for the final time?
Approaching 38, Federer's stunning fourth-round exit marked only the second time in 16 years the Swiss has not reached Melbourne Park's semi-finals.
Federer told the Herald Sun last month he is yet to schedule beyond the end of this season.
As world No 3 - with a rankings slip to about No 6 now unavoidable - it's hardly crisis time.
But how much time is left?
In ending Federer's 17-match Open winning streak, Stefanos Tsitsipas drove the most decorated man in grand slam history to distraction.
And, as uncharacteristic errors flowed from Federer's normally impregnable forehand wing, there were equally unfamiliar flashes of irritation and frustration.
As outstanding as Federer has been over the past two seasons, with three majors crowning a brilliant revival, his past three losses at the highest level were not at the hands of Novak Djokovic, Rafael Nadal or Andy Murray.
At Wimbledon, sabotaged by a wrist complaint, Federer let slip a two-sets lead over eventual finalist Kevin Anderson.
In New York, John Millman proved too formidable in the US Open's heat and, against Tsitsipas' bludgeoning raw power, Federer was occasionally made to look helpless.
As valiantly and proudly as he fought in sluggish conditions, Federer was unable to impose his silken game well enough for long enough.
Losing to rising star Tsitsipas is hardly reason to hasten into retirement with Wimbledon and the US Open offering title opportunities.
But, even though it is out of his control, Federer will want to bow out - whenever the day comes - predominantly on his terms.
He has made the point that the ideal opportunity to leave the game on the highest of highs came and went with 2017 Australian Open finals victory over Nadal.
Federer leaves Melbourne with a 97-14 record from 20 main draw campaigns since 2000.
Whether he returns to the Open remains to be seen. Let's hope there is a final curtain call next January.