The 20-year-old, who was also making his first start in the top flight, scored Spurs' second goal during the 5-1 rout at White Hart Lane last night.
The striker told the club's website: "It's the best feeling in my career so far. I was buzzing to get my first start in the Premier League for Spurs and to then get my first Premier League goal at White Hart Lane in a 5-1 win made it a brilliant night.
"I've waited patiently and to get that goal is a very proud moment. The goal put us 2-1 up and as soon as I scored it, the emotions just came out.
"I thought we played well before Sunderland's goal but we settled down and knew if we played well we'd score goals, that's how it turned out."
Tottenham currently sit sixth in the Premier League table.