Starting the match 23 points behind the Brussels club Lierse took the lead in the 25th minute from Mbaye Diagne. Anderlecht pushed hard for an equaliser but in the 65th minute Watt turned a half chance into a goal shooting home from 20 yards out with his fifth goal in four matches since Christmas.
The win lifts Lierse upto 10th place in the 16 team Jupiler League- seven points clear of the relegation zone.
After taking a little time to adjust to the change in environment Watt seems much happier in Belgium as he admitted after the match.
“My aim is to score as many goals as possible and try to help Lierse to take maximum points,” the striker said. “I feel good in Belgium and who knows, maybe I’ll stay longer than expected. in this country. I’m happy. “
Even happier was coach Stanley Menzo after Lierse’ first win over Anderlecht in 13 years.
The Lierse coach said: “Especially in the first half we played close to perfection, we played good football and bothered a great side like Anderlecht.”
Next Saturday Lierse are away to bottom of the table Mons.
6 min 15 sec for Tony’s goal
The success of Watt on loan has led to a flood of young Celtic players moving out for the remainder of the season with four joining Scottish Championship sides.
Joe Chalmers and Stuart Findlay could be in direct opposition when Falkirk host Morton while Mikey Miller could de in direct opposition to Paul George when Dumbarton travel to meet Hamilton Accies.