The Heed have had a promising pre-season so far but suffered a reality check on Saturday.
Wins over Dunston UTS, Motherwell and Billingham Synthonia were followed up with draws against South Shields and Whitby Town.
But last weekend a young Newcastle side put three past the Heed without reply.
"It's good to go up against a team like Newcastle because they're obviously got some really good young players, who are capable of playing at a very high standard," Aspin told the club's website.
"Although it isn't nice to lose any game, it was good that we were properly tested because their movement and passing was certainly up a level to what we have played so far this pre-season.
"There is no denying that we need to get much better before the season starts. We need to see when we play at our own level, how we can utilise our strengths in order to pick up results.
"Last season we started well with a couple of wins and when you do that, it doesn't matter how good or poor your pre-season was, all people care about and all that matters is how we start in the league."