Frankie Dettori is likely to choose Echo Of Light over Librettist in the Breeders' Cup Mile at Churchill Downs next Saturday.
The Italian admitted on Friday he is leaning towards the improving four-year-old, who won a Group Two at Longchamp on his latest start from the Godolphin pair.
Dettori said: 'I have not made a final decision but I'm leaning towards Echo Of Light.
'He is still a bit babyish, but he is maturing all the time. I think going left-handed will suit him.'
Echo Of Light is due to gallop today, while dual Group One winner Librettist has successfully come through his final piece of work before heading out to America.
Trainer Saeed bin Suroor said: 'Librettist worked over seven furlongs with Frankie Dettori on Racecourse Side. It was routine exercise and he went nicely.'
Christophe Soumillon is on standby to partner Librettist, according to www.godolphin.com.
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