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.
20. August 2017
|Stenson grabs third-round lead after late birdie barrage|
|Wenger: I´m not thinking about signing players|
|Holder: West Indies were totally outplayed by England|
19. August 2017
|Halep sets up Muguruza Cincinnati final and closes on world number one spot|
|We never give up - Simeone lauds Atletico escape act at Girona|
|Buffon ´sorts out problems´ for Juventus - Allegri|
|Broad hails special moment as he overtakes hero Botham|
|Championship Review: Hourihane a hat-trick hero in Villa thriller, Cardiff and Ipswich stay perfect|
|Wenger defends Ozil, hopes to have Sanchez back against Liverpool|
|Dimitrov breaks new ground with Cincinnati win over Isner|
|Broad eclipses Botham as England storm to victory by an innings and 209 runs|
|Girona 2 Atletico Madrid 2: 10-man Atleti battle to draw after Griezmann sees red|
|Hughes lauds ´elite´ Jese after Stoke´s gritty Arsenal upset|
|Coetzee demands more from improving Springboks|
|We scored a goal – Wenger disagrees with Lacazette offside call in Arsenal loss|
|Who needs the ball? Stoke beat Arsenal despite lowest-ever 22.7% possession mark|
|Montella dismisses talk of Milan title challenge|
|Zidane hoping for a big season from Bale at Madrid|
|Pulis hails ´absolutely fantastic´ debutant Barry after win at Burnley|
|Arnautovic apologises to West Ham fans after red-card shame|
|We cannot look back - Valverde keen to move on from Neymar and Madrid disappointments|
|Stoke City 1 Arsenal 0: Jese hits winner in dream debut|
|Bilic upbeat despite West Ham heartbreak at Southampton|
|BMC impress with time trial win as Froome gains early Vuelta advantage|
|Spalletti determined to keep Candreva despite continued Chelsea speculation|
|No news on Coutinho despite reported new Barcelona bid, says Klopp|
|Juventus 3 Cagliari 0: Buffon saves Serie A´s first VAR penalty in comfortable win|
|Marvellous Muguruza ends Pliskova hoodoo to reach Cincinnati final|
|Richarlison link-up excites Watford record signing Gray|
|Valverde calls on Barca to support Messi after Suarez injury|
|Shakespeare targets more home comforts after downing Albion|
|South Africa 37 Argentina 15: Dominant Springboks maintain winning streak|
|Klopp ´completely happy´ as Liverpool battle to win over Palace|
|Carlsson breaks down Wall to set up Siem semi|
|Swansea in race against time to do ´good business´ after Sigurdsson exit|
|Southampton 3 West Ham 2: Austin settles five-goal thriller with late spot-kick|
|Bournemouth 0 Watford 2: Richarlison shines to inspire Hornets victory|
|Leicester City 2 Brighton and Hove Albion 0: Okazaki´s early opener sets Foxes on their way|
|Liverpool 1 Crystal Palace 0: Mane rescues Klopp from more Premier League frustration|
|Burnley 0 West Brom 1: Sub Robson-Kanu hits winner, then gets sent off|
|Lynagh slams schoolboy Wallabies´ display|
|Dominant All Blacks were seduced by scoreboard, says Hansen|
|Wolfsburg 0 Borussia Dortmund 3: Pulisic shines as Bosz makes ideal start|
|Mourinho insists United will not get carried away after dream start|
|Cheika confident Wallabies will be better after first-half horror show|
|Confident United an improvement on last season - Pogba|
|Dembele will only leave Dortmund for right price - Zorc|
|Seahawks left tackle George Fant out for season with ACL injury|
|Smith staying focused after Storm secure minor premiership, Cowboys´ woes mount|
|Swansea City 0 Manchester United 4: Mourinho´s men win big again after late goal glut|
|Gotze to make first Borussia Dortmund start in seven months|
|Juventus´ Keita pursuit ´practically a crime´|
|Read thrilled by ´awesome´ All Blacks first half in Sydney|
|Australia 34 New Zealand 54: All Blacks run riot before Wallabies rally|
|Zidane open to new Real Madrid arrivals before transfer window closes|
|Hoeness slams Barcelona´s Dembele pursuit as ´the lowest class´|
|Mahmudullah overlooked as Bangladesh recall Nasir and Shafiul|
|Liverpool star Mane has Diouf dilemma|
|Nadal offers condolences to victims of Barcelona tragedy|
|Alexander-Arnold should expect to spend time on the bench - Klopp|
|Kyrgios on Nadal victory: These matches aren´t the problem|
|Sigurdsson feared Everton deal would collapse|
|All Blacks flanker Kaino returns to New Zealand|
|Machado´s walk-off grand slam lifts Orioles|
|Portland Timbers 2 New York Red Bulls 0: Hosts bounce back in MLS|
|Nadal fails to reach Cincinnati semis, Thiem falls to Ferrer|
|Pliskova set for Muguruza semi, Halep wins through|
|Kyrgios stuns Nadal in Cincinnati quarters|
|Mourinho has faith in Man United forward Martial|
|Nationals´ Scherzer on 10-day DL|