With confirmation that Serena Williams will not play for the remainder of 2017, there is a G.O.A.T.-shaped hole to be filled on the WTA Tour.
The 23-time grand-slam winner confirmed on Wednesday she is pregnant with her first child.
Williams is aiming for a return to competitive action in 2018, having apparently won the Australian Open while carrying her baby if a "20 week" timeline she suggested in a since-deleted Snapchat post is accurate.
The American is likely to spend an entire grand-slam cycle - if not longer - away from the court, so Omnisport's Matthew Scott looks at who is best-placed to fill her mighty shoes as top dog.
Lest we forget, the German is world number one as Williams begins her sabbatical.
@serenawilliams!! You will be such an amazing mother and I wish your family health and happiness for the best journey in the world— Angelique Kerber (@AngeliqueKerber) April 20, 2017
After a difficult start to 2017, Kerber has begun to regain her form and reached a first final of the year in Monterrey last time out.
Kerber fell at the first hurdle at the Madrid and Rome Masters in 2016, as well as the French Open - leaving a glut of rankings points up for grabs if she can get her game together on clay this year.
Don't @ me.
The only player Sharapova has ever suffered a continued struggle against is... Serena Williams.
Sharapova holds career head-to-head advantages over Kerber (4-3), Venus Williams (5-3), Karolina Pliskova (1-0) and Garbine Muguruza (3-0) - each of the non-Serena grand slam finalists since she was suspended from the game.
And with her return from a doping ban coming just as her great rival is stepping away from the limelight, it gives the 30-year-old another motivation ahead of her comeback in Stuttgart next week.
Arguably no player on the WTA Tour currently has as much upward momentum as the world number seven.
In the space of two years, Konta has gone from world number 151 to breaking the top 10, with her sights already set on the very top.
After securing the biggest win over her career against Caroline Wozniacki in the Miami Open final, Konta said: "I play smart tennis and calmer tennis, I think."
Konta's three WTA titles have come in the past nine months and she has only lost one final to date, proving her burgeoning big-game temperament.
With two titles to her name already in 2017 backing up last year's run to the US Open final, Pliskova has risen to a career-best ranking of third in the world, leaving her in pole position to challenge Kerber for top spot for the time being at least.
Like the German, Pliskova will have plenty of points to make up on during the clay season and only a second-round defeat in Dubai blots an otherwise solid copybook from 2017 so far.
Wins over fellow top-10 players in Brisbane, Qatar and Indian Wells suggest the Czech has the appetite for the big occasion.
The Belarussian has as far to go to reach the top as anybody in this selection, Sharapova aside, but Azarenka's progress will be fascinating, once she returns to action after giving birth to her first child.
Today I had my hardest fight and my very best victory! Our son was born healthy and happy! So thankful and blessed! Thank you pic.twitter.com/zsoFRivnvQ— victoria azarenka (@vika7) December 20, 2016
Victories in Indian Wells and Miami last year - which included wins over Kerber and Serena - hinted that the two-time major winner was back to her best.
Azarenka has won seven of her nine career meetings with Kerber and is one of few players in possession of power even remotely similar to Serena.
If the 27-year-old can hit the ground running, it will suggest that Serena can too, so any of the above will have to be quick if they are to make the most of the WTA Tour queen's absence.
|Pierre leads Dinamo Sassari past Pinar Karsiyaka|
|Willian: Chelsea will keep fighting for Premier League title|
|Burnley aren´t the real deal – Dyche|
|Stoger wants to bring best out of BVB after breakthrough victory|
|Conte praises contribution of Hazard, Willian and Pedro|
|Inter 0 Pordenone 0 (AET, 5-4 on penalties): Nagatomo spares Serie A leaders´ blushes|
|Hodgson keeping Palace grounded despite dramatic late win|
|Zouma injury led to Turf Moor defeat – Hughes|
|Guardiola steers carefully around Mourinho criticism after United v City flashpoint|
|Guardiola considering January signings to bolster Manchester City squad|
|Get me in the mix – Ricciardo wants to join Vettel, Hamilton rivalry|
|Crystal Palace 2 Watford 1: Sako, McArthur stun Hornets|
|Huddersfield Town 1 Chelsea 3: Willian sparkles as Conte´s side return to winning ways|
|Burnley 1 Stoke City 0: Hosts go fourth after late Barnes winner|
|PSG escape punishment as LFP gives Lille transfer ban|
|Mainz 0 Borussia Dortmund 2: Stoger´s tenure begins with much-needed victory|
|Need to wrap a golf club for Christmas? Don´t ask Dustin Johnson for help|
|Ten Cate: Al Jazira will park three buses against Real Madrid|
|Gremio 1 Pachuca 0 (after extra time): Everton stunner sends Brazilians into final|
|Zidane focused on Club World Cup despite looming Clasico|
|Ibrahimovic brands Guardiola ´immature´ over Barcelona row|
|Gayle´s 18 sixes a new T20 record|
|Pogba has no regrets over rejecting Real Madrid|
|Gattuso denies contract rift with AC Milan goalkeeper Donnarumma|
|Where you at? Cleared Fury calls out Joshua|
|Pochettino: Alderweireld out until February|
|Wydad Casablanca 2 Urawa Red Diamonds 3: Marvellous Mauricio double proves decisive|
|Cardona given five-match ban for ´discriminatory´ gesture against South Korea|
|Fury clears comeback hurdle as UKAD proceedings resolved|
|Knee injury rules Wales´ Faletau out of Six Nations|
|James still settling at Bayern, says Heynckes|
|Pistorius bruised in alleged prison assault|
|Manchester City captain Kompany out for ´a short time´|
|Klopp: Liverpool need Lallana ahead of busy period|
|Spurs list Leonard as probable for season debut|
|It was diversity in education – Mourinho addresses derby fracas|
|I encourage City to celebrate - Guardiola defends players after Old Trafford controversy|
|I´m no actor – No regrets for Klopp over heated interview|
|Anderson: Duckett incident a non-event|
|Shingler commits to Scarlets|
|Everton were like United at Liverpool - Allardyce defends Anfield approach|
|Paulo Bento hired as Chongqing Lifan head coach|
|Wolfpack and Toulouse to make Magic Weekend history|
|Ramsey hamstring injury ´not a big one´|
|Watford´s Zeegelaar gets three-match ban as appeal is rejected|
|Struggling Northampton sack Mallinder|
|Matthaus raves about Spurs star Kane|
|Cook: England must improve damaged reputation|
|´Several clubs´ discussing Arda move as Barca exit nears|
|No ultimatum as Arsenal´s Ozil and Sanchez talks rumble on|
|Su-Mourinho? Wenger offers advice to City and United|
|Bayern planning ´serious talks´ with Robben, Ribery|
|Titans lure Roosters veteran Gordon|
|Hazlewood welcomes Johnson advice and eyes Root scalp|
|Pereira replaces Villas-Boas at Shanghai SIPG|
|Van Gaal rejected Leverkusen to hold out for a ´big club´|
|Cook dismisses retirement talk heading into 150th Test|
|Williamson lauds record-equalling Taylor as Kiwis celebrate series win|
|Dolphins stun Brady and Patriots|
|Inzaghi and Lazio left feeling ´defrauded´ after Torino defeat|
|Marsh confident and ready to heap misery on England|
|New Zealand sweep Windies with 240-run victory|
|Man United more boring under Mourinho, claims Van Gaal|
|Rodgers return a medical decision for Packers|
|Stanton rips ´unprofessional´ and ´circus times´ with Marlins|
|Zidane: Real Madrid want to win Club World Cup|
|Worker to open batting as Guptill misses ODI series|
|Stanton excited to step into ´winning environment´ with Yankees|
|Morata ruled out of Huddersfield trip due to ´impossible´ workload|
|Valverde singles out Hazard & Morata as chief Chelsea threats|