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´m done - Gatland quits British and Irish Lions|
|Bosz and Dortmund eyeing much-needed victory as Schmelzer returns|
|Tiger Woods cleared to resume golf activities with no restrictions|
|Szczesny: I didn´t improve at Arsenal due to tactical gulf|
|Spurs coach Popovich calls Trump a ´soulless coward´|
|Bowman signs one-year deal with Raiders|
|Girardi says Yankees star Judge isn´t getting calls ´because he´s so tall´|
|Baldwin feared he could lose hand after lion bite|
|Pochettino wants ´10 or 15 years´ at Tottenham|
|Shakespeare hails Mahrez response after ´kick up the backside´|
|Packers QB Aaron Rodgers to undergo surgery on broken collarbone|
|NBA Eastern Conference Preview: Can Celtics´ bold moves unseat Cavs?|
|NBA Western Conference Preview: Everyone´s looking up at the Warriors|
|NBA Preview: Five rookies to watch in 2017|
|Cornet breezes past home hope Makarova in Moscow|
|Leicester City 1 West Brom 1: Mahrez cancels out Chadli magic|
|Hamsik not worried by Maradona record ahead of Man City clash|
|Joshua to fight Takam after Pulev pulls out injured|
|History for Babar as Pakistan see off Sri Lanka|
|Man City better than Real Madrid? Sarri daunted by Napoli´s Etihad assignment|
|Donaldson downed in Antwerp, Sela sees off Coric|
|Ashley puts Newcastle United put up for sale|
|Lovren accuses ´nervous´ Lukaku of deliberate kick during Manchester United draw|
|One small step for Ox... Klopp praise for under-fire midfielder|
|Klopp denies Liverpool have lost confidence|
|Manchester ready for goal rush as Spurs visit fortress Bernabeu - Champions League in Opta numbers|
|Packers are not done, but must be different with Hundley at helm|
|Police renew appeal for Stokes witnesses|
|Tottenham one of Europe´s best, claims Riedle|
|Watch: Barcelona mark Messi debut with footage of La Masia magic|
|Ronaldo has to win Ballon d´Or, says Isco|
|Guardiola not falling for De Laurentiis´ Napoli script change|
|Rhys Webb out in the cold as Wales scrap ´Gatland´s Law´|
|Button: I wasn´t to Hamilton´s taste as McLaren team-mate|
|Guardiola´s ´genius´ inspiring Sterling at Manchester City|
|He is a complete forward – Zidane an admirer of Kane|
|Bale could miss both Tottenham games, concedes Zidane|
|Wilder: Joshua doesn´t sound too confident|
|Guardiola takes pressure off De Bruyne amid Messi comparisons|
|Sarfraz: Sri Lanka should not have issue over Lahore T20|
|Napoli should rest stars against Manchester City - De Laurentiis|
|Switzerland, Italy, Croatia & Denmark seeded for World Cup play-offs|
|Kessler comeback delayed by Lyme disease|
|Kane takes Real Madrid interest ´very naturally´, says Pochettino|
|Packers coach McCarthy quiets free agent QB talk after Rodgers injury|
|Chelsea struggling to fight on several fronts, Conte concedes|
|Jiangsu Suning confident Capello not Italy-bound|
|Mo´unga called into All Blacks squad for Bledisloe Cup rubber|
|Dodgers take 2-0 NLCS lead over Cubs after walk-off win|
|High-profile injuries continue as Rodgers hurts collarbone|
|Pochettino: Madrid are not the Ronaldo team|
|Boateng considered Bayern exit|
|Nonsense! Critics won´t force Postecoglou out says Socceroos great Moore|
|MLS Review: Sounders, Timbers book play-off spots|
|Kaepernick files collusion grievance against NFL owners|
|Lukaku dismisses suggestions he is a flat-track bully|
|Milan will go along with Montella - Fassone backs boss after derby loss|
|Keselowski avoids Talladega carnage, wins on last-lap pass|
|Valencia win incredible nine-goal thriller at Betis|
|Spalletti hails Inter´s derby hero Icardi as complete striker|
|D´Ambrosio was clever - Milan boss Montella angry at Inter´s winning penalty|
|Tom Brady sets record for regular-season wins with controversial victory|
|Mandanda breaks Marseille appearance record|
|Inter hero Icardi ´holding on tight´ to derby hat-trick ball|
|Woods ´making progress´ with latest comeback|
|Pochettino watches you everywhere - Fonte|
|Attack proving best form of defence for Manchester City|
|If they think that, they will be stupid - Guardiola rules out City complacency pre-Napoli|
|Inter 3 AC Milan 2: Brilliant Icardi treble breaks Rossoneri hearts|
|Wales draw up shortlist for Gatland´s successor|