Still on a high after the birth of his first child and a purple patch in the saddle, Andrea Atzeni is dreaming of an upset win aboard Top Dragon in Sunday’s BMW Hong Kong Derby (2,000m) at Sha Tin.

Victory in the city’s most prized race would cap a whirlwind couple of weeks for the Sardinian jockey, who became a father just hours after celebrating his best winning haul in Hong Kong – a four-timer at Sha Tin on March 8.

Atzeni revealed he almost missed the Sha Tin meeting after his fiancée Emma’s waters broke that morning.

“I dropped her off at hospital before the races and I wasn’t actually sure if I was going to ride or not,” Atzeni said.

“The doctors told us Emma could be there six, seven or eight hours before anything was going to happen, so I was able to go racing. The hospital is just up the road from here, so I said to [Jockey Club steward] Terry Bailey ‘if they ring between races, just let me know’ but we got through the card, managed to get a few winners and got to hospital about 6.30pm and Thomas was born three hours later.

“It was a pretty good day. It was pretty strange knowing you’re about to have a child and still riding, but I was so busy. I was fully booked, I won the second and the third and everything was going quite smoothly and I kept asking Terry ‘was there a phone call yet?’ and he said ‘no, everything’s fine’.”

As he settles into life as a new father, Atzeni is keen to experience another first as he eyes his first triumph in the race everyone in Hong Kong racing wants to win.

Top Dragon heads into the Derby with a consistent record of three wins and six placings from 13 starts, fresh from a close second to Stunning Peach over a mile in his latest appearance.

In what shapes as one of the most open editions of the Derby in recent years, Atzeni rates the Chris So Wai-yin-trained gelding a solid chance.

“I see him as a lively outsider. You’ve got the main guns – Numbers, Stormy Grove, Little Paradise and Invincible Ibis. Any of those could win a Derby but I think after them, my fella comes in with a bit of a chance,” said Atzeni, whose hot form has seen him rise to third behind Zac Purton and Hugh Bowman in the jockeys’ championship.

“He can definitely run well. Can he win a Derby? I don’t know but if he did win, it wouldn’t be a surprise either.

“He’s pretty consistent. He ran well the last day behind Stunning Peach and that horse is improving and looks like he could be a Group horse in the making. The Classic Mile run was also good – he got hampered at a crucial stage of the race and he did well to finish fifth. He was around the horses he’s going to be taking on in the Derby, so I think he’s got a nice chance.”

Atzeni conceded the distance will be a query for Top Dragon, who is yet to race beyond 1,600m.

“That’s the question mark, but a lot of times you don’t need to be a 2,000m horse to win the Derby here – it just depends on the tempo of the race, the draw and luck in running,” Atzeni said.

“I’d rather they not go too quick because he’s stepping up in trip and has a good turn of foot, but hopefully we can get an even tempo. It would be nice to get a kind gate – he’s not a horse you can rush anyway, he’s a horse that puts himself in a position where he’s comfortable and hopefully he’s hitting the line strong.”

Atzeni almost pulled off a famous upset in the Derby two years ago on Ka Ying Generation, who led and burst clear in the straight before being run down in the final 50m for third to Massive Sovereign.

“I thought I had it in the bag. Obviously you win races at the winning post, not the 200m mark when I looked at the screen and thought I had it,” he said.

Meanwhile, Zac Purton has picked up the Derby ride on Seraph Gabriel after James McDonald was unable to get on a flight from Sydney.