Knowing that it had been coming doesn't make it any less seismic. Serena Williams will retire from tennis shortly after the US Open which starts later this month.
In an interview published today, the 40-year-old said she would be "evolving away" from the sport.
Twenty-three-time Grand Slam champion Williams is 25/1 to bow out by winning women's singles title at Flushing Meadow. Some will say that even that price is based on former-glories rather than recent form.
It would be an extraordinary achievement if the 40-year-old were to enjoy a fairytale ending and one which would put her level with Margaret Court's record 24 women's Slams.
Williams won her first Grand Slam title at the US Open in 1999, when she was 17, and went on to win it on five more occasions, most recently in 2014.
She won her last Grand Slam in 2017, at the Australian Open, and was knocked out of Wimbledon in the first round in June after returning from a long injury lay-off.
On Monday, she achieved her first singles win for 14 months when she beat Spain's Nuria Parrizas Diaz in straight sets to reach the second round of the National Bank Open in Toronto.
Iga Swiatek 9/4 is the outright favourite in the women's draw at the US Open which starts on 29 August.
The Pole won the French Open for the second time earlier this year but crashed out of Wimbledon in round three when she had been backed to go all the way.
From a British perspective, all eyes will be on defending champion Emma Raducanu.
The 19-year-old stunned the tennis world last year to take the title after coming through qualifying.
She is 25/1 to retain the title - something that nobody has achieved since Serena's three-year winning streak from 2012 to 2014.