The game settled again after that frantic period, with Franco narrowly off target as he set his sights from distance.

Vipotnik had a shot blocked after Darling had thundered into win the ball and sent substitute Liam Cullen careering forward. 

At the other end Malcolm Ebiowei fired wastefully over for the hosts inside the final 20 minutes, and Grimes made an unbelievable block to deny Scarlett.

And it proved an important moment as the Swans struck from their next attack with Bianchini sweeping home from Franco’s through ball.

Scarlett found the far corner for the hosts to set up a frantic finale, but the Swans took the spoils.

Swansea City: Lawrence Vigouroux, Josh Key, Ben Cabango, Harry Darling, Josh Tymon (Kyle Naughton 84); Matt Grimes (captain), Joe Allen (Liam Cullen 55), Gonçalo Franco (Cyrus Christie 84); Ronald, Myles-Peart-Harris (Azeem Abdulai 84), Žan Vipotnik (Florian Bianchini 71).

Unused Substitutes: Jon McLaughlin, Nathan Tjoe-A-On, Nelson Abbey, Aimar Govea. 

Oxford United: Jamie Cumming, Ciaron Brown, Elliott Moore (captain), Josh McEachran (Will Vaulks 60), Mark Harris (Dane Scarlett 60), Louie Sibley (Idris El Mizouni 46), Ben Nelson, Owen Dale (Malcolm Ebiowei 60), Tyler Goodrham, Ruben Rodrigues (Greg Leigh 82), Peter Kioso.

Unused Substitutes: Mat Ingram, Sam Long, Hidde Ter Avest, Will Goodwin.

Referee: Michael Salisbury

Attendance: 11,454