Chris Waller's Melbourne Cup team has been reduced to three with the trainer deciding not to try to push Beaten Up to the race.

The defection of Beaten Up leaves Sertorius at No.24 in the Cup field with trainer Jamie Edwards facing an anxious wait until after the Lexus Stakes on Saturday.

The Lexus is the final chance for a horse to force its way into the Cup with the winner guaranteed a place if nominated for Tuesday's race.

The Lloyd Williams-owned Moonee Valley Cup winner The United States is now one outside the field at No.25.

Beaten Up had been entered for both the Lexus and the Mackinnon Stakes but will be saved for the Queen's Cup a week later.

Waller's Cup contenders are 2014 Victoria Derby winner Preferment, Sydney Cup winner Grand Marshal and Who Shot Thebarman, third in the last year's Melbourne Cup.