Perth Cup favourite Ballack needs to win at Flemington on Saturday to convince trainer Danny O'Brien he is worthy of heading west for the New Year's Day feature.Ballarat Cup winner Daka's Gem and Eclipse Stakes winner Eskimo Dan are also in the Perth Cup and are among Ballack's rivals in the Western Health Cup (2000m).The O'Brien-trained Vigor was also entered for the Western Health Cup but will instead run in the Johnstaff Projects Plate (1700m) at Flemington while Group One-winning stablemate

Perth Cup favourite Ballack needs to win at Flemington on Saturday to convince trainer Danny O'Brien he is worthy of heading west for the New Year's Day feature.

Ballarat Cup winner Daka's Gem and Eclipse Stakes winner Eskimo Dan are also in the Perth Cup and are among Ballack's rivals in the Western Health Cup (2000m).

The O'Brien-trained Vigor was also entered for the Western Health Cup but will instead run in the Johnstaff Projects Plate (1700m) at Flemington while Group One-winning stablemate Valedictum was nominated for both races but will miss the meeting.

Ballack controversially beat Fast Future on protest in the Group Three Tatt's Cup (2200m) at Eagle Farm in June and raced three times in the spring with his best effort a last-start second to Road To Rock in the Chris Isaak Handicap (2000m) at Flemington on November 8.

O'Brien said Ballack was a promising stayer and got his chance to win again at Flemington.

"He is going well and if he won on Saturday he would probably go to Perth," O'Brien said.

TAB Sportsbet on Tuesday quoted Ballack as $7 favourite for the Perth Cup ahead of Mike Moroney-trained Mission Critical ($7.50) who finished fifth in last Saturday's Group One Kingston Town Classic (1800m).

Railway Stakes winner Gilded Venom is at $8, Annenkov ($8.50) and Eskimo Dan at $9 along with Guyno and Bold Scene. Daka's Gem is a $14 chance.

O'Brien considered taking Vigor to Perth but decided against the trip believing the four-year-old son of O'Reilly needs more seasoning.

"Probably next spring he will be ready for bigger stuff," O'Brien said.