The 18-year-old struck twice in his first six minutes on the pitch as Celtic scored three goals in the final half hour to win 3-0 at Fir Park.
Watt would not have played had he not been suspended for tonight's Scottish Youth Cup final against Queen of the South at Hampden, but manager Neil Lennon decided to give him some game time at Motherwell and he buried two fine goals. Johan Mjallby, Celtic's assistant manager, said that despite also having Gary Hooper, Georgios Samaras, Anthony Stokes, Mo Bangura and Pawel Brozek available, the young Scot is in contention when Rangers come to Parkhead this weekend.
"He's definitely going to be in our thoughts," said Mjallby. "The boy comes on and scores twice for you in a very tough away game against Motherwell, so he's obviously going to be in our thoughts. He's mentally strong as well which is good because if you are going to be a Celtic player the pressure is always there."
Watt joined Celtic in a £100,000 move from Airdrie 15 months ago but was made to wait for his chance. "We've had our eyes on him for some time," said Mjallby. "He's done really, really well for the under-19s. He's a strong, powerful boy and he likes to get in the box and score goals. We need strikers who are hungry for goals, so we are delighted for him. He has to keep his feet on the ground now because tomorrow in training the boys will try to kick him and out-muscle him, but he has a great future."
Mjallby said discussions had begun with the Celtic board with a view to making three or four summer additions who could help the squad compete at Champions League level.
"We are quite happy with the squad, no question, but if you look to the Champions League then we need maybe three or four really, really good players. But it's a bonus to have Tony and he's definitely going to be in our plans."
The defeat means Motherwell remain three points ahead of Dundee United in the attempt to finish third and reach next season's Champions League qualifiers. "It's disappointing to lose 3-0 having been in a good position at half-time," said manager Stuart McCall. "But I'd much rather be three points ahead of Dundee United than three points behind. It's all to play for. There was no lack of desire or effort today, it was just that little bit of quality."
McCall also spoke for the first time since Merseyside Police revealed that his midfielder, Steve Jennings, had been cleared after an investigation into alleged match fixing.
"Remember the furore when it first came up? And when he got arrested out of his bed there was talk, I don't know if it was from the SFA, of suspending him. Imagine if we had suspended him now that all charges have been dropped. Absolutely crazy. Will anyone face questions over that? But I think the club did really well and stood by him. It's been a cloud hanging over him."