Williams has had a tremendous career, but is clearly well past her peak
Serena Williams' aim of equalling the great Margaret Court's Grand Slam singles record is nothing more than a pipe dream.
And her sister Venus should retire - why she is still playing on the professional circuit remains one of tennis' modern-day mysteries.
Indisputably one of the greatest players of all time, Serena's last Grand Slam win was at the Australian Open four years ago when she defeated Venus in straight sets.
Since then she has been runner-up twice at Wimbledon - in 2018 to Angelique Kerber and 2019 to Simona Halep. She was also runner-up on another two occasions at her home Grand Slam at Flushing Meadows - in a controversial loss to Naomi Osaka in 2018 and the following year to Bianca Andreescu.
Ranked No. 11 in the world, her form in last week's Yarra Valley Classic had been impressive before withdrawing from the semi-finals with a shoulder injury. While she is still capable of challenging the 10 women above her in the rankings on her best form, the likelihood is that she will come up short again in this year's Australian Open, even if she makes it through to the quarter-finals. Players such as world No. 1 Ash Barty, Halep, Osaka and Sofia Kenin are younger and more athletic than Williams.
As a mother and successful businesswoman, Williams, 39, has several other time-consuming interests.
Equalling Court's record of 24 Grand Slam singles titles would be a big motivation for the proud American, but her accomplishments speak for themselves.
While Serena is going for her eighth Australian Open victory, Venus has not won a singles title at Melbourne Park and her Wimbledon loss to Garbine Muguruza in 2017 was her last appearance in a Grand Slam final.
Of her seven Grand Slam wins, five were at Wimbledon and two at Flushing Meadows, but the last victory was over her sister at Wimbledon in 2008.
Her ranking has slipped to No. 80 in the world and she was eliminated in straight sets during the second round of the Yarra Valley Classic by Petra Kvitova. Last year, the former world No. 1 won only one of her nine matches.
Venus, 40, has enjoyed a marvellous career, but she is well past her peak.
Cricket's missing inductees
Last week it was cricket's opportunity to honour three of the game's greats.
Popular, big-hearted fast bowler Merv Hughes and women's captain and prominent commentator Lisa Sthalekar joined indigenous all-rounder Johnny Mullagh as the most recent inductees into Cricket Australia's Hall of Fame.
The trio have undeniable credentials and thoroughly deserve their accolades, but as with Halls of Fame in other sports there is frustration and bewilderment for those who have been overlooked for honours.
In my view there are several glaring omissions to CA's honour board.
Ian Johnson was a member of Bradman's Invincibles team in 1948 and captained Australia in 17 Tests during the 1950s.
The off-spinner, who died in 1998 aged 80, took 109 wickets at 29.19 in 45 Tests and was a handy lower-order batsman.
After retiring from the game, he earned a reputation as a progressive administrator.
Ian Redpath and Keith Stackpole are former Test vice-captains who were outstanding contributors with the bat. Redpath, 79, played 66 Tests and was equally proficient as an opener and in the middle order, scoring 4737 runs at 43.45.
An excellent close-in fielder, "Redders" finished his career with a flourish, scoring three of his eight Test centuries against the West Indies in 1975-76.
Stackpole, who started his career as a leg-spinner and lower-order batsman, developed into a pugnacious opener and superb slips fielder.
In 43 Tests he scored 2807 runs at 37.42, including seven centuries with a top score of 207 against England in 1970-71.
"Stacky", 80, reserved his best for the old enemy, averaging 50.60 in 13 Tests against the Englishmen.
After retiring from Test cricket, he continued his involvement in the game as a commentator and respected coach.
More recently, pacemen Mitchell Johnson and Brett Lee sit in fifth and sixth places in the list of Australia's leading Test wicket-takers.
Johnson, 39, took 313 wickets in 73 Tests at 28.40, with Lee, 44, not far behind with 310 in 76 Tests at 30.81.
Both were also competent lower-order batsmen.
Crosswell also deserves honour
While on deserving candidates for Hall of Fame honours, Brent Crosswell should be at the top of Australian football's list.
My wife and I caught up with Crosswell on a recent trip to Tasmania and are happy to report he is in relatively good health at 70.
Despite dealing with the long-term effects of Meniere's disease - an inner-ear disorder that can cause severe vertigo, hearing loss and hallucinations and prevents him travelling to the mainland - Crosswell was erudite, engaging and entertaining when we met him at his favourite coffee shop.
The versatile Crosswell was at his best in finals during a distinguished 222-game career with Carlton, North Melbourne and Melbourne.
He played in two premierships with the Blues and another two with the Kangaroos.
Already an icon of Tasmanian football, he should be recognised in Australian Football's Hall of Fame.
- This article is supported by the Judith Neilson Institute for Journalism and Ideas