But the Irish maestro didn't have to wait long to snare his record-equalling 25th group 1 winner of the season.

It was just a matter of hours, in fact, until his unsung heroine Hydrangea capped a tremendous season for both herself and her handler by winning the group 1 British Champions Fillies and Mares Stakes at Ascot in the early hours of Sunday morning [AEDT].

Her win, in the hands of regular O'Brien jockey Ryan Moore, means the lrishman has now equalled the world record total of 25 group 1 winners in a season set by legendary American trainer Bobby Frankel, after whom the equine champion Frankel was named.

O'Brien still has several weeks to go in the flat season to grab another group 1 winner, which would put him alone in the pantheon of group 1 winning trainers.

There are major events in Europe, America (where the Breeders Cup will be staged in early November), Asia (Hong Kong and Japan) and, of course, in Australia, where a small but select team of Coolmore horses will look to give him that all important 26th success at the highest level.

While the O'Brien-trained The Taj Mahal will struggle to make his presence felt if he fronts for the Cox Plate against Winx, Johannes Vermeer certainly put himself in the Melbourne Cup picture with his unlucky third at Caulfield.

The five-year-old son of Galileo stepped more slowly than was ideal from the barriers and was unable to make the most effective use of his good gate (stall two) to take a prominent position on a track that had been dominated by leaders and horses who raced on the pace most of the day.

His jockey, Ben Melham, caused interference as he looked to get through, and copped a 12-meeting suspension which will keep him out until November 2 - five days before the Melbourne Cup.

Melham said: "He just took a step backwards as the barriers opened and I wasn't quite happy with where I was. I would have liked to have been a couple of spots closer in the run but, nevertheless, he was in a good rhythm, he was breathing and he was relaxed.

"We had to pick our way through the corner and he was really strong at the line."

Those last words would sound encouraging for the horse's prospects in the Melbourne Cup, a race in which O'Brien has saddled a placegetter (Mahler) but never a winner.

The Irish-trained galloper is now on the second line of betting for the Cup behind the English-trained Marmelo, who put in a storming effort as one of the few horses to make any ground from the tail of the field when he finished sixth at Caulfield, and last year's Cup winner Almandin from the Team Williams camp.

Hydrangea will hold a special place in O'Brien's memory for her feat on Saturday, but had things gone a little differently at Ascot he might already hold the record.

His top stayer Order of St George, the galloper part-owned by Lloyd Williams, took out the Long Distance Cup over 3200 metres, but that was one of only two races on the six-race Champions Day card that was not designated group 1. Order of St George was originally nominated as top weight for the Caulfield and Melbourne Cups but the Coolmore camp elected to stay in Europe, where he ran fourth in the Prix de l'Arc de Triomphe before winning on Saturday.

O'Brien also had to settle for group 1 places with Caravaggio, Churchill and Highland Reel on the same day. The latter is well known to Australian punters, having run third two years ago to the great Winx when she won her first Cox Plate.