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.
|I had to say a few words to the boys - Klopp|
|49 all out: RCB register record low in humiliating defeat to KKR|
|Nadal: I could never have dreamed of 10 Monte-Carlo titles|
|Montella expects battle for Europe to go to final game after Empoli loss|
|Bale shakes off injury to start Clasico, Alcacer replaces Neymar|
|Schalke 1 RB Leipzig 1: Huntelaar frustrates title contenders|
|Wenger: Sanchez is an animal and he will be at Arsenal next season|
|Bravo ruled out of IPL|
|Arsenal have answered the critics, says victorious Wenger|
|Liverpool 1 Crystal Palace 2: Eagles soaring to safety as Benteke stuns Klopp|
|Guardiola humbled by Sanchez but should resist tiresome transfer chase|
|PSV 1 Ajax 0: Locadia all but ends visitor´s title hopes|
|Hull, Wigan close in on Super League leaders|
|Rain postpones NASCAR Cup race at Bristol|
|Arsenal 2 Manchester City 1 (aet): Sanchez winner sends Wenger´s men into FA Cup final|
|Dyche unhappy with United goals|
|Fast start key as Clermont set up Saracens final|
|Mourinho confirms Ibrahimovic, Rojo face surgery on knee injuries|
|Rooney feeling strong after comeback goal|
|Victorious Valverde dedicates Liege-Bastogne-Liege win to late Scarponi|
|Toulouse 1 Nice 1: Favre´s men suffer hefty blow to title challenge|
|Lazio 6 Palermo 2: Keita nets five-minute hat-trick|
|Burnley 0 Manchester United 2: Rooney makes goalscoring return in Ibrahimovic´s absence|
|AC Milan 1 Empoli 2: Suso pays the penalty as Rossoneri´s European bid takes a hit|
|Nastase hit with ITF suspension|
|Amla follows up ton with match-winning half-century for Kings XI|
|Perfect 10 for Monte Carlo master Nadal|
|Everything has gone wrong - Icardi bemused by Inter woes|
|Daniel Wanjiru wins London Marathon, Mary Keitany sets women-only record|
|Stade book final spot as Lions reject Ford fluffs lines|
|Aston Villa 1 Birmingham City 0: Agbonlahor condemns Redknapp to derby debut defeat|
|Celtic 2 Rangers 0: McGregor, Sinclair down Old Firm rivals to keep Bhoys´ treble hopes alive|
|Sassuolo 2 Napoli 2: Milik rescues Sarri´s side after Hamsik howler|
|Rooney returns for United to replace injured Ibrahimovic|
|Mbappe, Silva and Lemar to stay at Monaco - Vasilyev|
|Wanjiru wins London Marathon, Keitany sets women-only record|
|Melbourne City 0 Perth Glory 2: Castro inspires Elimination Finals revenge mission|
|Griezmann considering Manchester United and Real Madrid offers|
|Clippers will be ready despite Griffin absence - Rivers|
|Lingard backs Rashford to fill Man Utd´s Ibrahimovic void|
|Wang wins in Zhengzhou as Peng retires|
|Fury withdraws from Parker WBO heavyweight title bout|
|Wiesberger holds nerve in Shenzhen play-off triumph|
|Anelka re-opens Domenech feud over Mbappe comments|
|Late Naiqama try seals Tigers win|
|Griezmann walks out on interview after questions over Atleti future|
|Neymar to miss El Clasico after Barcelona lose patience with TAD appeal|
|Younis Khan refutes retirement U-turn rumours|
|Man Utd is not a step up for Lukaku - Koeman aims barbs at Red Devils|
|Hazard understands semi-final benching|
|Red cards, penalties and controversy - Is Pique right to fear Madrid bias in El Clasico?|
|Arsenal v Manchester City: Aguero reasserting himself after Guardiola transformation|
|Stanley Cup playoffs three stars: Blues beat Wild as Rangers, Oilers also advance|
|Grizzlies edge Spurs, Warriors rally|
|Cubs overcome Reds, Carrasco delivers|
|MLS Review: Dallas stay unbeaten, Union denied first win|
|Wenger compares Ramsey to Lampard|
|Warriors star Durant to miss game three|
|Blue Jays place Tulowitzki on 10-day DL|
|Sane: Guardiola told me to play like Messi and Neymar|
|Sanchez almost at same level as Messi – Guardiola lauds Arsenal star|
|Kerr will not coach Warriors in game three|
|Chappell grabs Texas lead heading into final round|
|Simeone hails clinical Atletico after seeing off Espanyol|
|Pochettino looks to bright future for Tottenham despite Chelsea woe|
|We threw away our credibility - Pioli slams Inter after hapless second-half showing|
|Bomb scare has helped pull Borussia Dortmund´s squad together, claims Tuchel|
|Amir takes five on rainy day in Jamaica|
|Chelsea´s unsung heroes win Conte praise after Wembley win|
|Sporting CP 1 Benfica 1: Lindelof cancels out Silva penalty|