Pressure tests will define Jewel Serious moonlight: Atlantic Jewel steps out at Flemington before chasing a 10th-straight win in Saturday's Underwood Stakes. Atlantic Jewel has already come within a length of the mid-race sprint of Black Caviar but still has some ground to make up to be seen in the same class as her fellow unbeaten star. Daily Sectionals' Vince Accardi says, on his data, Atlantic Jewel is at the outstanding level after nine starts but the times expert needs to see her under pressure to find out if she is world class. "In a horse's first nine starts you can establish what the top capabilities of a horse are in terms of a sprint," Accardi said. We have that with Atlantic Jewel now but it will be her next few starts that define her. You find out from starts 10 to 15 what level a horse can go to. Atlantic Jewel is the only horse on my records that has got within a length of Black Caviar with her mid-race turn of speed. No other horse has done that for 400 metres and that is how good she is. She's shown that she can hold that speed for 400m, which is outstanding, where Black Caviar's sprint was 800m, but that is, of course, over shorter journeys. I still have her about six lengths behind Black Caviar and about two lengths behind Pierro and All Too Hard. But we have not seen her in those pressure situations where horses can run to their peaks. Accardi doubts Saturday's Underwood Stakes at Caulfield will deliver that pressure, but in the Turnbull Stakes and Cox Plate, which trainer Mark Kavanagh has pencilled in to finish her spring, Atlantic Jewel should face her moment of truth. "There doesn't look to be the early speed to take her out of her comfort zone on Saturday and her run last week showed she is still building," he said. When she gets in a solidly run race we will find out a lot more about her because there is definitely lengths of improvement in her. Daily Sectionals data show the only times Atlantic Jewel has been in races run with above-average early sectionals, she produced an acceleration from the 800m to 400m that her rivals couldn't match. They were both at group 1 level, her Thousand Guineas win, when she went 5.3 lengths better than average, and her All Aged Stakes victory, in which she recorded 11.3 lengths better than average for the 400m section. "Her data at the moment has her in the top five horses for the past couple of years, but she could step up those rankings and fit in just below Black Caviar with improvement," Accardi said. She is tracking to give a career-best performance but the question that has to be answered is how she will react under real pressure. We haven't seen that this preparation. It is a lot harder for horses to hold their sprints for longer as races get to towards 2000m, [and include] more pressure, and it is hard to set yourself apart from the rest at a mile and beyond. Her record of nine straight wins shows she is outstanding because she just keeps winning and the data backs it up. Her next couple of starts will define her career and whether she is truly in the elite class.