Glen Boss continued a hot streak as Private Steer staged an astonishing last-to-first win in the $2.5 million (Australian funds) Doncaster Handicap (Aust-I) today at Randwick.Private Steer, an 11-4 favorite, had twice struck trouble and been a conspicuous last in mid-stretch. The 4 year-old filly then launched a brilliant run through near the inside of the other 19 runners.Private Steer and Boss won the $1 million Stradbroke Handicap (Aust-I) at Brisbane, Queensland last June. It provided the second southern group I winner for Danehill Dancer. The Coolmore stallion also had group I successes on two continents in 2003 with high class sprinter Choisir.Boss's current streak of carnival group I wins started in the AJC Sires' Produce Stakes (Aust-I) at the AJC's Fall Carnival opener two days earlier. He replaced the suspended Chis Munce, who piloted Dance Hero (by Danzero) to victory in the $3 million Golden Slipper Stakes (Aust-I) on April 3.Danzero and Danehill Dancer are sons of Danehill.The Queensland-born Boss also forged a successful partnership with Starcraft (by Soviet Star) in the $2 million Australian Derby (Aust-I), the headline race on April 10.Again in the Doncaster, it was almost at the wire that Private Steer cut down last year's winner Grand Armee (11-2), who is by another on the Coolmore roster, Hennessy.Grand Armee was ridden by Dan Beasley, in the saddle when 100-1 shot Braeloch almost stole the Derby. The runner-up, by a long neck, was one of four entries saddled by Gai Waterhouse in her bid for a record-equalling seventh Doncaster. The mark is held by her late father, Tommy Smith.Ambulance (8-1) completed a 1-2-3 by Coolmore sires, the son of the deceased Grand Lodge holding down third 1 1/2 lengths away. The 1:35.57 for the San Miguel-sponsored mile was almost two seconds outside the race record on a track dampened by rain.Prepared by John O'Shea, 34, Private Steer has won just over $3 million and 10 races from 17 starts. Bred by Angelis Vasili, the filly was an $18,000 buy-back from a Tamworth sale in country New South Wales as a yearling.Boss said he knew his mount couldn't win after striking trouble fore the second time and dropping out last of the 20."I was thinking of excuses," he continued. "I just tried to remain calm and trust in her ability. "At the 50 meters she broke clear and made up so much ground I couldn't believe it. It's incredible what a soft win it was in the end."