Paul O'Sullivan may be having a quiet season, but he has found a promising youngster in Sante Fe Sun, who made an eye-catching debut in a rich Class Three Pak Sha O Handicap (1,200m) on Monday.

Sante Fe Sun was a maiden handicap winner in his Australian debut over 1,000m at Muswellbrook by 31/2 lengths as the favourite over eventual six-time winner Texan Lad. He then switched to the big-league track at Rosehill when sixth and third in two more juvenile starts over 1,200m - both on wet tracks.

The three-year-old moved well in three trials since arriving - rating nicely to win a final jump-out on March 8 over 1,000m at Happy Valley.

The gelding drifted in the market to 110-1 and came out of barrier 14. He was taken back a distant last about 14 lengths off the leader Xi Ying Men while finding a position one off the fence at the 900m. He was still at the tail about nine lengths down upon straightening waiting for a run behind Beauty Sparkle and Smart Kids, gained a clear run at the 200m and surged late to go down by 23/4 lengths behind the promising quartet of Bullish Friend, Bundle Of Joy, Exciting Dream and the newcomer Master Sommelier.

It looks a rich form race for the future and Sante Fe Sun will be climbing higher than his current rating of 67 and prove a tough cookie next time out.

He is a son of young stallion Haradasun and Bianconi mare But I'm Serious.

Haradasun established himself as a top-flight performer, notching seven wins from 1,100m to 1,607m including the Queen Anne Stakes at Royal Ascot over a straight mile.

But I'm Serious was a useful racehorse herself, winning six times over 1,200m to 1,600m and 10 times placed.