Maturity may be the part of the puzzle that is missing but John Size-trained Eastern Express has all the other qualities he needs to claim the HK$18 million BMW Hong Kong Derby at Sha Tin this afternoon.

Size has won the race twice in the past four runnings, with Fay Fay in 2012 and Luger last year, and saddles up a powerful hand today in Sun Jewellery (Ryan Moore) and Eastern Express (Karis Teetan).

Sun Jewellery held the front running over his stablemate on all terms – higher in the handicap ratings, more experienced and certainly more decorated, and hasn’t put a foot wrong with three wins and a second from four starts, including two Group Ones.

He overcame difficulties to win the Classic Mile when his stamina was on trial the first time and then did it again in the Classic Cup when he had to go 200m further again and came through with flying colours.

Meanwhile, Eastern Express has taken a different route. He began this campaign as a maiden, a horse who had never won a race, and Size knew he had to ask a lot more of Eastern Express just to make his way to this race. So he has had six races, rising through Class Four and Class Three before Size rolled the dice to ensure a place in the big game with a leap into the Classic Cup.

Whatever faith Size had in the staying-bred son of Fastnet Rock up to that point, it became fully vindicated when he stayed on strongly to claim a share of third, beaten only a neck by his star stablemate Sun Jewellery despite almost 30 points between them in the handicap ratings.

It was the run that confirmed he belongs in the Derby, and it was the fork in the road for Sun Jewellery and Werther (Hugh Bowman), after the latter had dominated Derby discussions until then.

The ones doing the hard work in running in the Classic Cup were Eastern Express and Blizzard (Gerald Mosse) as they chased a fast lead. While they were passed by Sun Jewellery and Werther, they did not surrender easily in the final 100m when sectional times demanded they should, and they were as strong as the quinella horses on the line.

Eastern Express is still in catch-up mode in terms of experience and maturity with all his main rivals but it didn’t show there and he has ticks in all the other boxes – tactical versatility, stamina and quality.

It’s a poor strategy to deny the claims of horses that win races, whatever the challenges ahead of them, and the big winning percentage of Sun Jewellery keeps him right in the picture as the big danger. He may not stay the 2,000m but then nobody really knows that yet.