Observer capped off a monumental Derby Day for Godolphin, Ciaron Maher and Mark Zahra with a commanding victory in the $2 million Victoria Derby at Flemington.

His win came shortly after stablemate Tentyris claimed the Coolmore Stud Stakes, handing Godolphin both major three-year-old features on the opening day of the Cup Carnival.

It was Zahra’s fourth win on the program, following earlier victories aboard Getta Good Feeling in the Wakeful Stakes and Warnie in The Damien Oliver.

Over in Sydney, Maher’s day continued when Jimmysstar landed the $3 million Russell Balding Stakes.

Pride Of Jenni later sealed a Group 1 double for the stable in the Empire Rose Stakes.

Observer’s development through the spring had been trending the right way, with his dominant Moonee Valley Vase success coming after a hard-luck story in the Caulfield Guineas.

“I think the sky’s the limit for this colt, he’s just so adaptable,” Maher said.

“He was unlucky in a Guineas, he’s won a Vase and now he’s won a Derby and he’s pretty similar to his old man.

“I’m rapt with our team. Mark (Zahra) is a great mate, he’s riding on a real crest of a wave and there’s nothing better than to win the Derby on Derby Day. It’s what it’s all about.”

Zahra committed to leading from gate four and controlled the Derby tempo from start to finish.

Observer ($2.45F) held Arcora ($61) by three-quarters of a length with Deal Done Fast ($31) close up in third.

“I ummed and ahhed whether to lead, but speaking to Ciaron he gave me great confidence,” Zahra said.

“I heard him say, ‘he’ll run it, so if you want to lead, just do it’. He never switches right off, he’s always on the bridle, but he’s tough.

“He’s just like his old man and late, when they got to him, he found again.

“It’s great riding for the best trainers. They do their job, I do my job and what a great day.”

The win was Zahra’s first Victoria Derby and Maher’s second following Hitotsu’s victory in 2021.