Honestly, it was sort of a fluke. Albeit quite an impressive one for his age. He defeated a 19yr old American who was at best a very very average national junior within his country in the first round. In the second round against the 4 seed he won in a retirement but it was in the third set. Who knows if the injury affected his opponent the entire time or if it just occurred at the end? The third round was an excellent and surprising win against a quality player that shows a lot of promise and mental toughness. But the semifinal was again against a teen, this time only 17.
To be fair, none of these matches (except the first round one) were ones he should have won. So really, it would have been a fluke if he had been like 18 or 19, but at 15 there are no easy futures matches.
He's beaten Balleret once before in Qatar, so he's already proven to beat top 500 players before, and Luke Bambridge has a lot of potential. I do agree, that he probably won't repeat this result for a little bit, but he's already proven to be able to get to the second round or further at multiple futures, which is still good for his age and in this era of tennis.