No other New Zealand-bred horse has achieved the historic Blue Diamond/Golden Slipper double, a feat accomplished by COURTZA in 1989.

COURTZA (1986–2002) was a champion New Zealand-bred thoroughbred racehorse best known for winning the prestigious Group 1 Golden Slipper Stakes in 1989. By the powerful North American sire POMPEII COURT (USA) out of HUNZA (Pakistan II), she would cement her legacy not only on the racetrack, but also in the breeding barn by producing one of New Zealand's finest ever sires in O'REILLY.

Waikato Stud Ltd, a publicly traded company, acquired Waikato Stud from American oil magnate Nelson Bunker Hunt and subsequently bred Courtza from Hunza, who was later recognised as the 1989 Broodmare of the Year. Courtza was offered for sale at the inaugural National Yearling Sale held at the new Karaka Sales Centre in 1988, representing one of only two fillies by Pompeii Court available. Noted owner Nick Columb acquired the filly for $300,000, and she was trained by Ross McDonald.

An accomplished equestrian who started his career as a gifted horsebreaker, Ross McDonald eventually began training in the mid-1970s and prepared a string of top-flight gallopers over the next 30 years. While McDonald trained in Melbourne (primarily out of Caulfield) rather than New Zealand, he had strong ties to the wider Australasian racing industry and handled numerous top-tier horses with New Zealand bred connections. The astute trainer prepared star galloper WEEKEND HUSSLER to win six Group 1 races and claim the 2007/08 Australian Horse of the Year title. McDonald also won thr Gr.1 Caulfield Cup twice with TRISTARC (1985) and IMPOSERA (1988). He was widely regarded as a master horseman and "horse whisperer" with an uncanny ability to rehabilitate wayward or difficult racehorses.

COURTZA ran second at Caulfield on debut in late January 1989, before finishing second at her second start in the Gr.3 VATC Blue Diamond Stakes Preview 1000m. Two weeks later she won the Gr.3 VATC Blue Diamond Prelude 1100m, and the following week she easily won the Gr.1 VATC Blue Diamond Stakes by four lengths. GOOD OLD TED established an early lead, maintaining it until COURTZA swiftly advanced early in the straight, ultimately outpacing the competition. Shane Dye executed a flawless ride, as the filly demonstrated remarkable agility and determination through to the finish line flicking and swishing her tail.

Starting as favourite from barrier (9), Courtza then went on to win the Gr.1 STC Golden Slipper Stakes at Rosehill Gardens, going away to win by a length and a half from PARIS OPERA with Shane Dye in the saddle - SHOW COUNTY would finish third. This victory marked the first of four consecutive Golden Slipper titles for jockey Dye, who went on to dominate the race from 1989 through 1992. Courtza became the first New Zealand-bred filly to land the Blue Diamond and Golden Slipper. No other New Zealand-bred has matched her historic double. Only LADY OF CAMELOT in 2024 and SEPOY in 2011 have completed the Diamond/Slipper double in the past 40 years.

The following spring, Courtza was back in action to run fifth in the Gr.1 MVRC Manikato Stakes, then won second up in the Gr.2 Ascot Stakes at Flemington. Seven days later she recorded another easy win in the Gr.2 Veuve Clicquot Stakes at Moonee Valley. She ran third to ZABEEL in the Gr.2 Moonee Valley Stakes, but after unplaced runs in the Gr.1 Caulfield Guineas, the Gr.1 WS Cox Plate and the Gr.2 VRC Wakeful Stakes in the spring and two further unplaced starts in the autumn, she was retired.

Her first foal was a filly by Danehill named DANZIGA, who never raced, and was killed by lightning at three. After missing to Danehill, Courtza was covered by Last Tycoon and sent back to the place of her birth, Waikato Stud. When Garry Chittick purchased Waikato Stud lock stock and barrel in 1994, Courtza was in a paddock alongside her weanling Last Tycoon (IRE) colt. That colt was, of course, O’REILLY who the Chittick’s, wisely, elected to retain.

O'REILLY became the dominant stallion at Waikato Stud following his racing career where he won the 1996 Gr.1 Bayer Classic and Gr.1 Telegraph Handicap before finishing 2nd to MOUAWAD in the Gr.1 Canterbury Guineas. A short six race career was ended when pulled up in the Newmarket, but he established four wins next to his name.

O’Reilly was a real Kiwi legend. Not only has he sired 96 stakes winners to date, but he was a dominant broodmare sire and his daughters have produced 29 Group 1 winners. The phenomenal success of O’Reilly at stud makes Courtza’s own broodmare career a little more heartbreaking. After foaling O’Reilly, she had a Sir Tristram colt that sold for $260,000 but he came to an untimely end when being broken in. She then had a dead foal by Centaine before producing a filly foal by the son of CENTURY in 1996. She was named O’REALLY and was retained by the Chitticks. After making a winning career debut at Avondale, O’Really had just two more starts for a fourth and a second but her worth was at stud. After missing to Centaine again the following season, Courtza returned to Australia for a date with Last Tycoon. On return to New Zealand, she foaled a colt named KINGMAKER. From three starts, Kingmaker won at Bendigo and Seymour before being beaten into second place at Sandown and did not race again.

After missing in 1999 and 2000, Courtza was euthanased at Waikato Stud the following season after she contracted peritonitis and had to be put down soon after foaling. Her Danasinga foal also died. The WW Cockram Stakes at Caulfield is historically referred to now as the Courtza Stakes in recognition of her elite juvenile excellence.

RACE RECORD - 14: 5 - 2 -1

STAKES EARNINGS - $1,848,550 i

Blue Diamond Prelude

Blue Diamond Stakes

Golden Slipper

Ascot Stakes

Veuve Clicquot Stakes