Swansea City will travel to Manchester United for next Saturday's 2104-15 Premier League opener on the back of a 3-0 friendly defeat by Villarreal.
On the day Spanish defender Chico Flores' departure was confirmed, his fellow countrymen were victorious at Liberty Stadium.
Ikechukwu Uche side-footed in the opener against Garry Monk's side.
After the break Bruno Soriano's free kick and Denis Cheryshev's header completed the win.
Swansea's recruits Lukasz Fabianski, Jefferson Montero, Bafetimbi Gomis and Gylfi Sigurdsson made their first appearances since signing in pre-season.
But Nathan Dyer was absent after being given time off for personal reasons.
Monk was also without injured Leon Britton, Jay Fulton, Marvin Emnes and Wayne Routledge.
The latter has a foot problem, but is expected to be fit to return to training ahead of the 16 August trip to Old Trafford.
Swansea City: Fabianski, Rangel, Bartley (Amat, 60), Williams (capt), Ki Sung-Yueng, Shelvey, Sigurdsson, Montero, Gomis, Bony.
Subs: Tremmel, Richards, Tiendalli, Kingsley, Sheehan, King, Bray.
Villareal: Asenjo (Carlos, ht), Gaspar (Rukavina, 33), Uche (Cheryshev, ht), Giovanni Dos Santos (Moreno, 52), Cani, Trigueros, Antonio Dorado, Costa (Jokic, ht), Paulista, Soriano (capt), Espinosa.
Subs: Nahuel, Jonathan Dos Santos, Vietto, Puerto, Marcos.