Who will replace Serena Williams as the WTA Tour ruler?
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.
ANGELIQUE KERBER
Lest we forget, the German is world number one as Williams begins her sabbatical.
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.
MARIA SHARAPOVA
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.
JOHANNA KONTA
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.
KAROLINA PLISKOVA
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.
VICTORIA AZARENKA
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.
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.