In-form Hartnell has re-acquainted himself with Moonee Valley ahead of what trainer John O'Shea has described as a vintage Cox Plate.
Hartnell was one of four Cox Plate contenders to gallop at Moonee Valley on Thursday morning, working solo over 1400m as did his stablemate Hauraki.
Queen Elizabeth Stakes winner Lucia Valentina pleased her trainer Kris Lees and jockey Kerrin McEvoy with how she handled her first look around Moonee Valley, working in company with Happy Trails who is on track to run in his fifth Cox Plate on Saturday week.