Auckland Reactor has opened up at a restrictive $1.05 on the TAB's final field market for the Cup Day junior free-for-all at Addington tomorrow.

The reason for the prohibitive price is simple.

"We just can't see any of the others getting remotely close to him," said TAB bookmaker Steve Richardson.

Artishake is second favourite at $15. Richardson said he wasn't expecting many straight-out bets at the $1.05 price, but the horse would be popular in multi-bets.

"Basically, he adds five per cent to the worth of multis."

Auckland Reactor is unbeaten in 12 starts, with the New Zealand Derby last season one of his victories.

He was sold for about $4 million earlier this year before suffering a mystery ailment that sidelined him for about four months.

At his only start this season, he galloped away in a discretionary pace at Ashburton on Labour Day, but recovered to beat Nearea Franco and recorded sizzling final sectionals.

He was slow away again at a trial last Wednesday, but finished a tough second to Monkey King, with Changeover third.

Safely through tomorrow's race, he will start in the NZ Free-For-All on Friday and will probably earn an invite to the Miracle Mile at Sydney later this month if he runs well.

He could well meet exciting 5-year-old Melpark Major who enhanced his Miracle Mile prospects with a stunning win in the Legends Mile at Moonee Valley on Saturday night.

Melpark Major maintained his unbeaten record this preparation in adding the group two feature to his resume.

The Alan Tubbs-trained pacer swamped his rivals in devastating fashion as he came from last in the nine-horse field.

So fast did Melpark Major, the $2.40 favourite, finish, that he won running away by 3 3/4 metres from Decorated Jasper ($7.60). Kilmore Cup winner Bold Cruiser ($27.30) ran home well to be a neck away third.

Melpark Major clocked a personal best time of 1:55.9 in winning the Legends Mile, a performance that is sure to impress the selection panel that issues invitations for the Miracle Mile at Harold Park on November 28.

Blacks A Fake has already been invited to contest the feature.

Melpark Major has won his past two starts, both over sprint distances, in brilliant fashion.

He rated 1:55.5 in winning the Popular Alm Sprint (1690m) and then lowered his career best time to 1:54.9 with his Legends Mile triumph.

- NZPA, AAP