Kay was crowned England Open boys’ champion at Chichester with victory over Sussex’s Alex Gurr.
The Plymouth Studio School pupil produced a dominant performance in the final, which was shown live on TV, beating Gurr 5-0.
He had earlier beaten Jamie Peetoom 3-0 in the semi-final and Lewis Sinagogo 3-1 in the quarters.
Kay’s toughest game of the tournament came in the last 16 where he met rival Jarred Cole.
The pair had clashed the week before in the final of the third Modus UK Tour event in Worcester, which Kay won.
The Plymouth teenager again got the better of his Hertfordshire rival in Chichester, triumphing 3-2. Kay, who has already qualified for December’s World Junior Championships, had overcome Lewis Gurney 3-0 in the first round.