Will Spain's Rafael Nadal surpass the Swiss master Roger Federer?
Wimbledon 2010 has been and gone, tossing up several lingering thoughts about three of the game's top men's singles exponents, the Williams sisters and the match that felt as if it would never end.
One question will go on being explored in the lead-up to the US Open, the fourth and final of the year's grand-slam tournaments: after Roger Federer's premature quarter-final exit at Wimbledon, has his record haul of grand-slam championships ended at 16?
Most likely, and sadly, yes, for the Swiss master, now almost 29, has clearly faltered. Although he won the Australian Open, he has not had a tour victory since, and his success in Melbourne was unquestionably aided by Rafael Nadal's injuries, which contributed to his early demise.
A second poser can be aimed at Nadal now that he has won his second Wimbledon crown. If he completes the full set of grand-slam titles by winning in New York, will he be ranked at the same level of greatness as Federer?
He should be, for it's rare for any player in the modern era to win each of the tournaments throughout his career, and close to impossible to clinch the genuine slam of all four in the same calendar year. Federer completed his full set of career successes by winning the French Open last year, but has never managed better than three grand-slam triumphs in the same year.
In age terms Nadal is even ahead of Federer; Nadal has just turned 24 and is already halfway to Federer's tally of titles whereas Federer was almost 25 by the time he had his eighth triumph in 2006.
Briton Andy Murray can only dream about the stratosphere in which Federer and Nadal exist. In the wake of another failure at Wimbledon - and this one was his to take - it's reasonable to ask: is he a choker? Yes. And will he ever win a grand-slam title? It's increasingly doubtful.
Like Federer and Nadal, the Williams sisters have never found grand-slam glory difficult to achieve, provided their heart, mind and soul have been in it. The remarkable Serena landed her 13th championship by winning at Wimbledon, and although many in the sporting world may ridicule her, she and sister Venus have inestimably helped to lift - if not always enhance - the profile of women's tennis. What would it be without them? Generally insipid, it would have to be said.
Of all the events and feats at Wimbledon this year, nothing surpassed the seemingly endless match and especially the extraordinary fifth set in the singles clash between American John Isner and Frenchman Nicolas Mahut. In a match lasting 11 hours and five minutes - the longest singles contest in history - Isner eventually won 70-68 in a fifth set that ran more than eight hours.
Inevitably the question was raised about whether to introduce a tiebreaker in the fifth and deciding set at Wimbledon. Given those circumstances, logic would say of course, but pure sporting sentiment - not to mention tradition - will always resist such a temptation.
Wimbledon is what it is for too many reasons to list here, but tradition encapsulates so many of them. That marathon fifth set couldn't be a better example.