Watch for surprises in Victoria Derby Complacent, ridden by Christian Reith, wins the Spring Champion Stakes at Randwick on October 12. For punters, classic races - in theory - should be the easiest to sort out. They pit horses of the same age against each other and all carry the same weight, so the class gallopers can be expected to stand out and have things to themselves. Sometimes it works out - Darley's two favourites, Guelph and Long John, both proved the rule in the Thousand Guineas and Caulfield Guineas respectively earlier this month, while odds-on favourite Savvy Nature, despite finding the tight Moonee Valley circuit rather difficult to negotiate, in the end had little difficulty in seeing off his rivals in the group 2 Mitchelton Vase on Saturday. But there is one race that quite often proves the exception and in some ways is the hardest riddle of all for punters to solve during the spring, as they simply have no idea which immature three-year-old will stay the trip. The group 1 contest is, of course, the Victoria Derby, which will be the centrepiece at Flemington next weekend. A group of lightly-raced and far from fully developed three-year-olds will set out on a journey into the unknown when they jump from the barriers right in front of the stands to begin their 2500 metre jounrney. None will have gone further than 2000 metres, and only a few will have even scored at that distance. But just because they can run that far there is no guarantee that they will get the extra 500 metres when the pressure is on down the Flemington straight. Breeding can give some assistance, as there are stallions that do have a great record in producing stayers, the legendary Zabeel being the best illustration. But, as any buyer or bloodstock agent can attest, there are no guarantees and horses can often turn their pedigree upside down. Shamus Award, for example, is by that hot sprinter Snitzel, yet he ran out the 2000 metres of the Cox Plate without any problems. A few years ago champion sprinter Miss Andretti proved herself just about the quickest horse in the world when she scooped all before her in Australia before winning over 1000 metres at Royal Ascot. Yet her sire was a horse whose best Australian win was the 2155 metre Benalla Cup in October 1997 and her dam was a daughter of Marooned, who won the Sydney Cup in the mid 1980s. On bloodlines, she should have been a Melbourne Cup winner, not a Newmarket heroine. So while it is tempting to look at this year's race and head to the top of the market nothing can be taken for granted. Darley looks to be in the driving seat with its three-year-old Complacent, who passed up on a chance for a blowout on Saturday in the Vase. Trainer Peter Snowden knows that winning a derby can be a war of attrition: "three-year-olds at this time of the year, they are all on the improve and its sometimes about which ones keep standing up. Complacent has had the prep to get straight to a Derby - he's had four runs," he said last week as he explained why he wouldn't run in the traditional Vase lead-up and take on Savvy Nature. The last of his four starts this spring was the one that catapulted him to favouritism for the race when the son of Authorised (himself an English Derby winner) took the group 1 2000 metre Spring Champion Stakes at Randwick over two of next weekend's rivals, Criterion and Savvy Nature. It was the brown colt's third win on the spin and he has gone from scoring in a Hawksbury maiden to a group 1 winner in barely a month, having also taken out the group 3 Gloaming Stakes along the way. On paper he should get the trip, but as Snowden says, until you ask them to try you just don't know. It is that hope which will give connections of slowly maturing horses some optimism that they can belie their starting prices next weekend and run big races over the extended trip. Last year's Derby result will certainly give them food for thought: Anthony Cummings' 40-1 outsider Fiveandahalfstar ground his rivals into submission to win under Damien Oliver, with David Hayes' three-year-old Rawnaq finishing fast and late to take third place at 100-1. And it's not so long ago that Clare Lindop became the first woman jockey to take the Blue Riband event on another 100-1 shot, Rebel Raider, who won in his year because he was, quite simply, the best stayer in the field.