IMO it's possible in rare cases. Ogata said Rimi was a genius, with talent only seen 1 out of a 1000 and he planned on using that talent to kill Miu. If that's the case how rare do you think the talent of Miu, Sho, Berserker, Siegfried and Kisara? IMO Kisara is less talented than Rimi, while Miu and Sho can't be much more talented than Rimi, since Rimi can compete with Miu, without Rimi needing to work as hard as someone like Kenichi to get results. Their talent (Sho and Miu) may be something like 1 out of 1500 due to their other talents Rimi may not have developed to the extent they have, for instance insight and willpower. So how talented do I think the likes of Siegfried and Berserker are? Maybe 1 out of 2000.
So if Miu and Sho are around the ballpark of Rimi's talent (1 out of 1000) the implication would be that it may be possible for lower class Martial artist to beat masters. Miu and Rimi have speed that rivals master class. Sho has a Master Class body. Kenichi has ki has reached the level of masters, ki holding. The point is disciple class can have abilities that rival Master Class. Imagine if Sho made it to intermediate expert class, his greatest abilities (speed and power) could of become far above a garbage class master abilities in the same area. Add the boost Sho would get from releasing his two ki's and then using them with Sei Dou Goui, his speed and power would be so great a garbage master probably wouldn't be able to deal with that.
What if there was a disciple who had a talent that was 1 out of 100,000?This hypothetical disciple would have master class abilities every area except technique, in which he would be disciple class in that area. Could you imagine how far he would get by the time he became a intermediate class expert? Garbage class masters would most likely get dominated.