But while the now-retired six-year-old has been awarded a rating of 131 – the highest since the publication began in 2004 – top quality performers were thin on the ground as a whole.
Manduro, who was unbeaten in five starts, achieved his best performance in the Prince Of Wales’s Stakes at Royal Ascot and lies 2lb ahead of four horses on 129 - Authorized, Curlin, Dylan Thomas and Invasor.
The rankings are decided by a committee of leading global handicappers and the co-chairman and senior Irish Flat handicapper Garry O’Gorman said: “We have five outstanding horses and it is rare that that happens but there might be a soft underbelly and not so many good horses behind them.
“The next best is Street Sense on 126, so there was more strength in depth last year, although this was generally a good year.”
Injury robbed Manduro of a chance to challenge Dylan Thomas again in the Prix de l’Arc de Triomphe but his general progress through the season had already earned the utmost respect of the handicappers.
O’Gorman continued: “He improved 11lb from his four-year-old mark and it is unusual for a horse to improve so much from four to five although not unprecedented – Daylami improved 12lb.
“But it was rather surprising to see him do so well on the context of his four-year-old form where he ran respectably but not to that level.
“A comparison this year would be a horse like Duke Of Marmalade, who was knocking on the door in the big races. That’s the sort of progression he made, but racing’s full of surprises.”
The head of British handicapping, Phil Smith, added: “It is unusual for a horse to produce the top performance of the year in the Prince Of Wales’s Stakes, rather than a race like the Arc but it was a stunningly strong race.”
Dylan Thomas was second that day before winning the King George, another of the best four world performances, each of which occurred in Britain.
The others belonged to Authorized in the Juddmonte International and the Derby, with Frankie Dettori and Peter Chapple-Hyam’s emphatic triumph in the Epsom Classic drawing generous praise.
“It was unusual in that the form actually worked out and we’ve got a cracking race,” said Smith.
“In the last 10 or 11 years, only Sinndar’s Derby was rated higher and it was nice to see the Derby winner actually win another race.”
Peeping Fawn and Darjina were rated the best turf fillies in the world on 122, although they were 1lb behind the first female to win the Belmont Stakes in 102 years, American ace Rags To Riches.
Darjina defeated Ramonti in the Prix du Moulin, but Aidan O’Brien’s quadruple Group One winner Peeping Fawn filled O’Gorman with joy.
“Peeping Fawn was a freak of nature this year as she did not even win on her first three runs,” he said.
“You only know how good these horses are until they get beaten, but hopefully she will train on and have a chance to take on the colts.
“We have three exceptional fillies, all staying in training, and let’s just hope they stay sound, as the likes of Ouija Board and Pride were nowhere near as good at this stage of their careers.”
The rankings also placed O’Brien’s Doncaster Cup winner Septimus (122) just ahead of his stablemate Yeats (121) despite the latter’s second victory in the Ascot Gold Cup.