The 18-year-old forward came off the bench in the 74th minute with the tie goalless with Ramsgate at Southwood Stadium.
Adebayo went on to score the only goal of the game in the second period of extra-time, when he fired home in the 110th minute.
He joined Ahmet Rifat’s side on loan for the rest of the season last month and helped the North London outfit win their second League Cup – they first won it in 2011.
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Afi Adebayo, pictured for Ipswich Town U21s this season. (Image: Ross Halls)
The versatile attacker has enjoyed his first taste of senior football, becoming a regular for the seventh tier side.
Adebayo has been at Town since Under-14s, becoming a full academy player in the summer of 2023 and signed his first professional contract with the Blues last summer.