The Swans made a dream start to their Europa League Group Stage campaign by stunning Valencia 3-0 at the Mestalla Stadium.
Michael Laudrup's side were hugely dominant throughout, and they took full advantage after Valencia were reduced to ten men following the dismissal of defender Adil Rami after just ten minutes.
They immediately showed their ruthless streak against the La Liga side as, just five minutes later, the Swans edged themselves ahead as club record signing Wilfried Bony fired past keeper Vicente Guaita.
The visitors had the majority of possession, territory and shots on target, but couldn't double their advantage before the break.
But they made sure they were heading back to Wales with all three points from their opening game in Group A in the second half.
Michu finished from close range after an excellent counter which started just 20 yards from their own goal, and then Jonathan de Guzman curled a sublime 30-yard free-kick into the top corner to really put the gloss on an unbelievable start to the Group Stage for Laudrup's men.
Next up in the Europa League is a home clash with St Gallen, of Switzerland, at the Liberty in October.
Michael Laudrup was without captain Ashley Williams due to an ankle problem while Pablo Hernandez also missed out against his former club through injury. Leon Britton was suspended after being dismissed in the previous round.
The Swans were captained by Angel Rangel, who led the club for the first time, with the right-back one of six Spaniards included in the starting XI.
Five changes were made from the side that drew with Liverpool last time out, with Jordi Amat, Jose Canas, Dwight Tiendalli, Jonathan de Guzman and Alejandro Pozuelo all given the nod.
Valencia made eight changes from their 3-1 La Liga defeat by Real Betis with defender Jeremy Mathieu, skipper Ever Banega and striker Helder Postiga retained by Serbian boss Miroslav Djukic.
Valencia: Vicente Guaita, Adil Rami, Sofiane Feghouli (Dorlan Pabon, 58), Helder Postiga, Ever Banega (capt), Javier Fuego, Andres Guardado, Antonio Barragan, Jeremy Mathieu, Sergio Canales (Juan Bernat, 66), Fede Cartabia (Ricardo Costa, 14).
Subs: Diego Alves, Jonas, Paco Alcacer, Daniel Parejo.
Swans: Michel Vorm, Angel Rangel (capt, Ben Davies, 55), Chico Flores, Jordi Amat, Dwight Tiendalli, Jose Canas, Jonathan de Guzman, Michu (Jonjo Shelvey, 77), Nathan Dyer (Roland Lamah, 65), Alejandro Pozuelo, Wilfried Bony.
Subs: Gerhard Tremmel, Garry Monk, Wayne Routledge, Alvaro Vazquez.
After some early threats from Sergio Canalas, who first saw his tempting cross along goal fail to meet a home body before firing low into the hands of Michel Vorm, the temperature raised even higher.
With ten minutes on the clock, Wilfried Bony outmuscled the hosts some 40 yards out after a clearance deflected off Michu, and when Bony pushed the ball past Adil Rami and headed for goal, the defender pulled the striker back and was shown a red card as he was the last man.
Valencia immediately made a change, Ricardo Costa replacing Fede Cartabia.
But, with 15 minutes on the clock, the Swans took full advantage of their extra man advantage.
Alejandro Pozuelo raced on and fed Michu down the left, and when his cross met Bony, the club record signing blasted a powerful effort past keeper Vicente Guaita from 12 yards following a slight deflection.
It could, and should, have got better six minutes later as sub Costa's attempted pass was intercepted by Dyer, who raced in on goal but scuffed his effort wide from an angle.
Bony then saw an ambitious overhead kick float harmlessly wide while Michu blasted a 20-yard volley high into the stands as the Swans continued to enjoy the majority of possession and territory.
Bony was a constant thorn in the Valencia defence, his power brushing Costa off the ball before a thunderous right-footed effort dropped wide.
The Swans probed further, Michu climbing high to meet Jonathan de Guzman's curling cross, but he failed to trouble Guaita in the last action of the half.
Half-time: Valencia 0 Swans 1
Buoyed by their first half performance, the Swans looked to protect their lead, but they went close to doubling their lead as Pozuelo drilled low at Gaita after Bony's shot deflected to him.
Bony then failed to direct Dyer's perfect cross in what was a good chance for Laudrup's side as they continued to attack.
Another great chance came the visitors' way as Chico Flores nodded on to Michu following a corner, but the Spaniard's shot cleared the crossbar from just ten yards out.
Laudrup then made a change, Ben Davies coming on for Angel Rangel - who passed the captain's armband on to Vorm - which saw Tiendalli move to right-back.
But just before the hour, the Swans did get the goal they deserved.
In a move that started at the edge of their own box, the Swans moved possession upfield through de Guzman and then Dyer, who found Pozuelo 20 yards out. And when the midfielder slipped in a pass for Michu, the former Rayo Vallecano midfielder thundered past Guaita from ten yards after 58 minutes.
But things got even better.
Just four minutes later, de Guzman stepped up for a free-kick and curled it into the top corner from 30 yards.
The Swans were in dreamland, and shortly after Laudrup made more changes as Roland Lamah replaced Dyer, while Jonjo Shelvey came on for scorer Michu in the 77th minute.
Neither team failed to trouble each other after that, with the Swans - and in particular the 2,000-strong Jack Army - enjoying the final moments of the match as they secured a famous victory against the former Uefa Cup winners.