The current tennis year began very much as a continuation of its predecessor, with Roger Federer winning another Grand Slam, and, just as at the Championships, Wimbledon last year, he beat Marin Cilic in the final.
However, the retention of Federer's title in Melbourne - along with the fact that Rafael Nadal could not repeat his run to the 2017 final - closed the gap at the top between the two men, and last month saw the Swiss legend retake top spot, adding another page to his one-man history book as he became, at 36, the oldest player to hold top spot in the ATP rankings. Having already spent a record 302 weeks of his career in first place, the 20-time Grand Slam champion was able to add some more.
The one problem for Federer was that, having won the ATP 1000 tournaments at Indian Wells and Miami last year, he was at risk of dropping points and swiftly relinquishing top spot. When he lost the final at Indian Wells to Juan Martin del Potro his position became more precarious, and his shock second round exit to world number 175 Thanasi Kokkinakis means Nadal will be back on top when the new rankings are published after Miami.
Moreover, the battle for top spot over the next few months is now really shaping up. Fans booking corporate hospitality for the Championships, Wimbledon will be among those wondering who will be top when the tournament takes place.
A key factor will be the clay court season. Following his exit in Miami, Federer announced he would miss the whole clay court season for the second year running, a clear admission that he believes a second French Open title is beyond him. The easy route back to number one of playing some clay court tournaments and picking up points is clearly being sacrificed for another tilt at Wimbledon.
However, that piles the pressure on Nadal. The brilliance with which he secured the French Open title last year after breezing through the clay court season suggested Federer was well justified in his decision. But, following his recent injury that forced the Spaniard to miss Indian Wells and Miami, it remains to be seen if Nadal can come back and match that performance.
Even if he wins the French Open again, Nadal might easily slip back into second while Federer has his feet up. Last year's clay court season saw the Spaniard win the ATP 1000 events at Monte Carlo and Madrid, with an ATP 500 win in Barcelona in between. His sole defeat came in the quarter finals of the Rome Masters. All that means the Mallorcan has a lot to emulate this year.
For that reason, Nadal's appearance at the Fever-Tree Championships at the Queen's Club in June could be significant. Last year he was due to appear at Queen's, but withdrew due to injury. If he were to win the tournament this year, that would give him another 500 ranking points.
Moreover, having lost in the round of 16 at Wimbledon last year, Nadal can pick up more points with a good run at the All England Club.
By contrast, Federer has maximum points to defend from his grass court exploits last year at Halle and Wimbledon, so the two summer tournaments in London will go a long way to deciding who will be number one a few months from now.
Image: Michael Dodge/Getty Images for Keith Prowse subscription