"He was pretty good last start considering the overall time and the fact he missed away, which actually surprised me," says Purdon.
"So even though Jack's Legend is a more proven horse at the top level Mach Shard might have a little edge on him this week."
Jack's Legend is a real deal open class player this season but Purdon's horses tend to improve with a run under their belt and that will almost certainly be the case tonight.
"I wouldn't be shocked if he won because we all know he is a very good horse but it is hard for them fresh up against horses like Star Galleria."
Purdon also has stunning debut winner Dream Major in tonight but he meets some hardened rivals in race eight, which looks a great early season form race.
"He is a pretty good horse but he will have some other smart young horses around him and potentially following him so it is a big step up."
Also returning tonight is National Trot winner Temporale, up against his arch rivals Lemond and Speeding Spur in a rare Alexandra Park mobile mile open grade trot.
Trainer Tony Herlihy is adamant the now six-year-old is bigger and stronger than last season, when a late growth spurt may have seen him weaken off and dip in form.
"He has been working well but we all know how hard it can be fresh up for them, especially when the other two have had a start this time in," says Herlihy.
A lot may come down to the start because if Lemond, who has the best draw of the big three, can get across and lead it is hard to imagine he will be attacked.
After trotting a very fast time fresh up off a 50m handicap last Friday he might be the best bet of the favoured trio tonight.
Tonight's mainly mile meeting also features an even bigger rarity, a standing start mile for the lower grade trotters which will see a new national record as — for now — there is not one listed.
Alexandra Park
• Best bet: The Player (R10, No3): Handy young trotter suited by mobile mile racing.
• Too slick? Star Galleria (R7, No8): Could be developing into a very good horse and manners will help overcome 20m handicap.
• Drawn helps: Lemond (R9, No4): Natural speedster drawn to stay in front of arch rivals.