The superstar mare, a sporting hero in Australia, won the last of her 25 races at Randwick on Saturday but there was no mention that run would be her last.
Officials at Ascot still hoped she would return to the Royal meeting after her heart-stopping win last June in the Diamond Jubilee Stakes, where she suffered a muscle injury which kept her off the track until February this year.
However, connections have decided to let their star bow out in full health.
“It’s been tough, we’ve been grappling with it (retirement) since Ascot,” said Werrett.
“We did very well to get three more wins out of her which were a positive for the whole team and Australian racing really.
“To get her back and win like she did on Saturday and in the Lightning a few weeks before was satisfying.
“It was always going to be a hard decision but it would have been a worse decision if you ran on and something happened, but now she can retire and we can look forward to racing her progeny.”
Her trainer Peter Moody nursed her back to her best after her eight-month absence, but he admitted she had little left to achieve.
“(The) owners and myself had a long chat over the last couple of days and at lunchtime today we decided 25 was a great number to go out on,” he said.
Moody admitted a second trip to the Royal meeting had been in the thoughts of connections for this year.
“Collectively the mare is in great shape. We thought long and hard about Ascot, Brisbane and Adelaide but it’s a good time to finish as she’s done everything we’ve asked of her,” said Moody.
“It’s time to pull the career of one of our finest horses ever.
“She’s got a few aches and pains but we always wanted to make sure she finished on a good note.
“After Ascot we were going to retire but in the finish we got three more runs out of her.”
Moody admitted her three wins on home soil this year were something of a bonus, not only for connections but also for Australian racing fans.
“We thought she would be retired post-Ascot,” he added.
“But we’ve been fortunate to bring her home here and I think the owners are to be congratulated on allowing me to race her on and give the Australian public three more opportunities to see her.”
Black Caviar was partnered by jockey Luke Nolen on all but three starts in a career spanning four years and she retires after earning over £4.5 million in prize money.
The daughter of Bel Esprit is set to say a final farewell to the track when she is paraded at Caulfield on Saturday.