The Wales Under-21 international, pictured, completed his hat-trick after just 20 minutes and added a fourth just before the hour mark, making it 17 goals for the season and 10 in January alone.
The Swans top Group D with seven points and qualify for the knockout stages of the competition for the first time in three years.
Everton finish fourth with one point from three matches.
A Callum Wright brace earned Leicester City a 2-1 comeback win over Dinamo Zagreb, but it was not enough to secure a spot in the last eight.
The Croatian side took the side after 22 minutes through Leon Sipos, only for Wright to strike twice in reply.
Leicester finish second in Group A with six points, but they miss out on being one of the two best-placed runners-up on goal difference.
See: Leicester report
Brighton & Hove Albion finished their International Cup campaign with a 3-2 defeat by Group B winners Wolfsburg.
Julian Justvan put the German side in front before Bojan Radulovic levelled for Brighton.
Anton Stach's deflected effort and a Mamoudou Karamoko penalty gave Wolfsburg a 3-1 lead, with Teddy Jenks grabbing a late consolation.
Brighton end Group B in third place with one point, while Wolfsburg finish top with a 100 per cent record.
Second-placed West Ham United reach the knockout round as one of the two best-placed runners-up.
See: Brighton report
The draw for the last-eight stage will take place on Thursday 30 January.