Grand Sydney galloper Theseo notched up Group One win number four when he held out a pair of stablemates in a thrilling edition of the Chipping Norton Stakes (1600m) at Warwick Farm this afternoon.

The Gai Waterhouse trained and Nash Rawiller ridden gelding showed his usual guts and determination to win the time honoured Sydney feature by a half head.

With Waterhouse in Melbourne, stable foreman Tania Rouse was left to represent the stable and she was all smiles in the winner's stall.

"He's just a marvellous, tough old horse," Rouse said. "I knew he'd keep sticking his head out when if became a ding dong battle."

"Gai has done a wonderful job to get him back to his top so quickly," she added.

And Rouse sent a warning to his likely rivals in the upcoming Ranvet Stakes and BMW saying Theseo had plenty more improvement in store.

Rawiller was also almost stuck for words to describe the outstanding galloper following his latest big race success.

"He is so tough," Rawiller said after the win. "He's a war horse."

Rawiller said eventual runner-up Rangirangdoo "definitely" hit the front in the straight but said his charge pulled out plenty when challenged.

"I don't know what else to say about the horse," he added. "He's had a lot of problems and I'm just really happy."

"Gai wanted him ridden like the best horse in the race," Rawiller summed up.

In a thrilling finish Theseo ($7) showed plenty of fight to hold out the challenge from the favourite Rangirangdoo ($2.70) to win by a half head.

The runner up's stablemate Danleigh ($7) was another length and three quarters back in third place.

A six-year-old gelded son of Danewin, Theseo is another outstanding success story for leading Sydney syndicator Denise Martin.

Buying under her Star Thoroughbreds banner, Theseo was purchased for just $120,000 from the draft of Emirates Park at the 2005 Magic Millions Gold Coast Yearling Sale.

As it stands he's now won nine of his 32 starts. His earnings have raced past $2.7 million.

Theseo is one of two stakes winners from his dam, the two-year-old winning and stakes performed L'Enjoleur mare Ozone Sand.

Aside from her four time Group One winner, Ozone Sand is the dam of the Perak Derby winner Gold Arrow.

Further back it is also the family of international group winners including Caller One, Queen Isolt, Cozzene's Prince, Prospect Bay and tough Aussie stayer Gillespie.

Theseo was one of three big race winners on the Warwick Farm card for Waterhouse - the other two being homebreds.

More Joyous continued her winning run with a fighting success in the Surround Stakes, while Dreamscape won the Liverpool City Cup.