William Buick book-ended his Rosehill program with winners as Godolphin's leading jockey steered stable stalwart It's Somewhat home to complement his first-race success on French import Spectroscope.

The Norwegian-born British hoop made the ideal start to his secondment in Sydney when Spectroscope scored the card-opening $100,000 Schweppes Handicap (1350m).

He then finished with a flourish in the eighth race when It's Somewhat ($9.50) claimed the Group Two $200,000 Ajax Stakes (1500m) by a long head from New Tipperary ($10).

Testashadow ($15) was a head further back in third.

Buick, 28, arrived in Australia last weekend and needed little time to acclimatise after being summoned to replace an injured James Doyle, the first replacement for New Zealand jockey James McDonald once he was disqualified on a betting charge.

"He's adapted really well, as did James," trainer John O'Shea said.

"They're a pleasure to have, we're honoured that his Highness (Godolphin founder Sheikh Mohammed) would think strongly enough to send them down here."

Buick, who will reassess his stay in Australia after next Saturday's $3.5 million Golden Slipper at Rosehill, where he will ride either Veranillo or Trekking.

"It's definitely not easy but it's a pleasure to come," Buick said, downplaying his success on Saturday.

O'Shea has mapped out the future of four-year-old Spectroscope and It's Somewhat with the former back at Rosehill in a fortnight for the Group Three $150,000 Doncaster Prelude.

It's Somewhat is being geared for another nudge at the Group One Doomben Cup where O'Shea hoped the six-year-old gelding would improve on last year's third placing.

"I thought we'd try and get him there on fresh legs. We might give him one more run in the Doncaster (on April 1) and see if we can't get a better result this year."

It's Somewhat, which scored first-up after a 21-week spell, lifted his earnings to $995,374 with his seventh win from 30 starts.

"He's been a great servant for us," O'Shea said.

"William gave him a little bit of persuasion at the two hundred just to encourage him along. It was a really good performance.

"We were really happy with our French import there first-up too."