There were suggestions that the teenager's attitude wasn't all it could be when the decision was taken to allow him to head away from Lennoxtown this season and get a loan deal under his belt.
And it hasn't been plain sailing for the forward who has scored just once for his loan side.
He has been sent home twice from training after run-ins with manager Stanley Enzo who has publicly criticised the youngster's work-rate and application.
But the striker, whose goal against Barcelona last October in the Champions League catapulted him into the full public eye, believes that he was unfairly judged by the Belgian media before he had the chance to do anything on the park.
"I never got a fair chance from the press, I was already in the papers before I touched a ball in Belgium," Watt said.
"I came here to Lierse and it started off with my name being in the newspapers before I'd even kicked a ball (saying) I was lazy, I don't think that's fair.
"I think I should be given time, I'm just a young lad, I should get time to settle in, it's hard being away from home.
"At that point, I was with my cousin. I just wanted time to play and I started off with negativity around me and you need to fight that. Hopefully I can fight it."
Watt made the move to Antwerp on the final day of the transfer season and he has not given up on being able to make an impact with the club in the second half of the season.
Celtic have been in contact with him, although "not a lot" and he is keen to make up for lost time.
In one appearance for Lierse he was on the park for just 40 seconds before being sent off against Charleroi. That was later shown to be a harsh decision and no suspension followed, but it hasn't been straightforward for the teenager to make the kind of impact that he'd have liked.
"I've learnt that I need to work hard," said the youngster. "I was very unlucky so far with injuries and didn't have that much playing time," he explains.
"I hope that I can show my talent in the next couple of weeks.
"I'm just getting back into fitness. I really need to be 100%."
Watt is confident that he can still make an impact at Celtic but is well aware that there are plenty of eyes on him while he is out on loan.
The 19-year-old badly needs a solid run of games and goals to improve his standing but he is optimistic that he can still turn things around.
And he doesn't believe that too much was expected of him after that goal against Barcelona 13 months ago.
"No, I think they expected just enough but I didn't play many games together after that match," he said.
"If I retire I want to have scored a lot of goals and won a lot of trophies.
"For this season, I also want to score as much goals as I can.
"I will do my best to succeed here in Belgium so I can become a better player for Celtic."