Donnacha O’Brien is leaning towards the Coronation Stakes with 1000 Guineas runner-up Porta Fortuna, but could still be persuaded to run his star filly in the Commonwealth Cup at Royal Ascot.

Victory at the Royal meeting eluded the 25-year-old during his time as a jockey, but the daughter of Caravaggio provided the County Tipperary handler with his first success at the summer showpiece as a member of the training ranks when landing the Albany Stakes 12 months ago.

Since then, Porta Fortuna has gone on to scoop Group One glory in the Cheveley Park Stakes, as well as rattle the crossbar at the Breeders’ Cup, and she also came mightily close to providing the trainer with his first Classic when second at Newmarket.

Although both a Group One winner and proven over the Commonwealth Cup track and trip, O’Brien is keen to continue plying Porta Fortuna’s trade over a mile, which could see a Royal Ascot rematch with Rowley Mile conqueror Elmalka and subsequent Irish 1,000 Guineas heroine Fallen Angel.

However, he is also keeping an eye on the weather forecasts and a wet week in Berkshire could easily see Porta Fortuna change tack and drop back to six furlongs.

O’Brien said: “Obviously, Porta Fortuna will be our main hope for Ascot and we’re still undecided on Coronation or Commonwealth.

“The ground will play a factor and there is some rain forecast. If they got some rain, then we would be more likely to go Commonwealth, but if it is good ground, then the Coronation would probably be more likely.

“She’s very straightforward and an easy filly to train, so it makes things a lot easier.

“I keep swapping and changing in my head what the best place is to go with her. I would be leaning towards the Coronation but if the ground came up soft, then we will obviously think about dropping back in trip instead.”

The young handler is set to have only a few runners over the course of the week, with Roscommon scorer Naval Force and the Niarchos family’s Yosemite Valley the others from the O’Brien stable who could cross the Irish Sea.

“We have Native Force in the three-year-old handicap, the King George V Stakes,” continued O’Brien.

“He won well at Roscommon first time out this year and I think he is a horse who will have a little squeak in that handicap.

“The only other possible would be Yosemite Valley in the Queen Anne, but he’s not guaranteed to go to the meeting.”