When Roger Federer announced 12 months ago that he was set to miss the US Open, the Olympic Games and the rest of the 2016 season, it felt like yet another brick had fallen out of the Big Four's steadily crumbling wall of dominance.
At that moment, Rafael Nadal, hampered by a persistent wrist injury and long-term knee problems, had not reached the final of a grand slam since June 2014.
And the extended departure of the Swiss master from the ATP World Tour circuit reduced the diminishing cartel at the head of the men's game to a Big Two, consisting of Andy Murray and Novak Djokovic.
The Serbian had stunningly surrendered his Wimbledon title by losing to Sam Querrey in the third round at the All England Club.
Djokovic also lost the US Open decider to Stan Wawrinka, a persistent thorn in the side of the dominant quartet, before giving up his number one status to Murray in November.
And as harsh as it sounds, the man who ascended to the summit of the world rankings was very much the runt of the Big Four litter, evidenced by his earlier defeat to Kei Nishikori in the last eight at Flushing Meadows and relatively modest slam haul.
At no other point in the previous five years had the ruling elite of men's tennis appeared so vulnerable.
Wawrinka, Nishikori, Marin Cilic and Milos Raonic lined up to seize their opportunity and break the stranglehold, with youngsters Alexander Zverev and Karen Khachanov considered long-term heirs to the throne.
Leap forward a year and Djokovic has followed Federer in calling time on the rest of his season, meaning the 30-year-old will miss the US Open, the ATP World Tour Finals and Davis Cup duty.
I took time to make a decision about my recovery. Sorry for keeping you in the dark these days. Read more here https://t.co/tCSw46TOL2-- Novak Djokovic (@DjokerNole) July 26, 2017
But rather than confirm the irretrievable demise of the Big Four, the Serbian's hiatus may instead contribute to the remarkable renaissance enjoyed by the sport's established heavyweights.
Federer surprised even himself by staging a wildly successful comeback this year, returning to action after five months out to win the Australian Open and Wimbledon.
Across the net in the final on Rod Laver Arena in January was none other than Nadal, who is also finally back to his best, and swept all before him during the clay court swing, culminating in a landmark 10th French Open victory.
Federer's triumph at the All England Club this month came after the 35-year-old shrewdly rested throughout the Spaniard's exploits on red surfaces in Monte Carlo, Barcelona, Madrid and Paris.
The players touted as the most likely to take advantage of the power vacuum have proven to be mere pretenders, their collective inadequacy encapsulated by the unfortunate sight of Cilic wilting before the majesty of Federer on Centre Court, while the next generation are not yet ready to regularly trouble the rejuvenated greats.
#19 tastes great pic.twitter.com/3Hv3lM5Rk9-- Roger Federer (@rogerfederer) July 16, 2017
The decision of Federer to take a lengthy break and plot a strategic route through the season could serve as a profitable model, not just for Djokovic but for Nadal and Murray too.
The Brit's Wimbledon title defence was badly undermined by a hip injury and, while he appears set to try and compete at the US Open, he could soon opt for a sabbatical of his own.
Received wisdom that the shelf life of professional tennis players does not extend much beyond 30 is being increasingly debunked, not just by Federer and Nadal but also the members of the ATP Tour's rank and file.
Gilles Muller, the man who overcame Nadal in a marathon at SW19 this year, is playing the best tennis of his career at 34, while Wawrinka (32), Jo-Wilfried Tsonga (32), Tomas Berdych (31) and Gael Monfils (30) all occupy places in the top 20 of the rankings.
Not far behind them in the top 40 are old stagers Ivo Karlovic (38), Feliciano Lopez (35) and David Ferrer (35).
The prospect of the Big Four taking measures to prolong their excellence is bad news for the second-rung challengers desperate to finally have a clear run at a slam but music to the ears of those hoping to continue enjoying the greatest period of sustained quality in the modern era.
So get well soon, Novak, and take heed, Andy. You're not going anywhere just yet. In the meantime, it's Roger and Rafa's turn to hold the fort.