Havana Rey has been a special horse to Bjorn Baker and capped a memorable day for the trainer's family with victory in the Group Two Ajax Stakes at Rosehill.

Havana Rey has been a major player in Baker's emergence in the Sydney training ranks in the past 18 months and he booked a spot in the Group One Doncaster with his Rosehill success.

The gelding's all-the-way win in the 1500m race came after It's A Dundeel, who is trained by Baker's New Zealand-based father Murray, scored by 6-3/4 lengths in the Group One Rosehill Guineas.

It's A Dundeel has been based at Bjorn Baker's Warwick Farm stable for his autumn campaign and is on target to claim the Sydney triple crown in the Australian Derby.

Havana Rey ($6) took up the running under Glyn Schofield and kept finding in the straight, holding off Riva De Lago ($12) by a length with Monton ($9) a half head away third.

The victory earned a ballot exemption into the Doncaster Mile.

"He's been a very special horse," Baker said.

"He only galloped very average on Tuesday and I was debating whether to even come here today. It's a funny game, this horse racing game."

Baker said Havana Rey was likely to push on to the Doncaster (1600m).

"He's a good horse and he makes his own luck," he said.

While Baker was celebrating the win of Havana Rey, trainer Gai Waterhouse said she would go back to the drawing board with the Queen's horse Carlton House who finished 13th in his Australian debut after jumping as the $4 favourite.

Waterhouse said jockey Hugh Bowman wasn't disappointed in the performance, saying the five-year-old was worked up in the barriers, raced keenly early and then had nowhere to go in behind horses until the turn.

"He said he definitely needs longer and you've just got to write off today," Waterhouse said.

"I've got a little bit of maintanence work to do and then hopefully we'll get the desired result."