The combination of trainer Danny O'Brien and Irish apprentice Oisin Murphy has continued its winning form with Second Bullet breaking his maiden with a 12-length win at Yarra Valley.

The Encosta De Lago colt, out of triple Group One winner Private Steer, was the $1.65 favourite in Tuesday's 1517m race at the picturesque Victorian country track.

Murphy, who is indentured to English trainer Andrew Balding, is midway through a three-month stint with O'Brien while Britain concentrates on winter jumps racing.

He won his first metropolitan race for O'Brien on Settler's Way at Moonee Valley on December 29 and followed that with a win in the Listed Bagot Handicap on the Nigel Blackiston-trained Outback Joe on New Year's Day at Flemington.

The Yarra Valley maiden was the third start for Second Bullet, who finished second on debut at Seymour in November and an unlucky fourth at Moonee Valley on December 20.

Murphy said the addition of blinkers had helped Second Bullet get away more cleanly.

"There's more improvement in him and I would be disappointed if he didn't step up and win a city race next time," Murphy said.

The trainer and jockey also combined at the meeting with the John Singleton-owned Please Leave who ran third in a 1017m maiden.