Leekens watched his side get thrashed 4-0 against the Magpies as Lokeren failed to match United.
The ex-Anderlecht and Trabzonspor chief said after the game: “I am not disappointed, they were much better.
“They had more class and technique.
“We tried our best but we gave away too many chances and every chance seemed to be coming towards our goal.
“We tried some things out in defence but we could see to improve little things and some players were missing.
“The judgement will come one week before the season when players are back.
“We played against a team and club that will be back very fast into the Premier League.
“I think when you look at the quality of their side and their coach I know I can put my money on Newcastle this season.”
And when asked if the defeat would crush team spirit at Lokeren, who played the game on their fan open day, he said: “It wasn’t exactly a League One or League Two club, this was a proper Championship team that should go up.
“They were better than us.
“There is no disappointment but I know we have some work to do.
“We have to work between now and our first league game.”