Southampton took their tally to seven goals in a week with another convincing win in south Wales, this time at the Liberty Stadium.
Hosts Swansea took the lead in bizarre fashion, as Mohammed Salisu sliced an innocuous cross into his own net, but Saints were behind for only 60 seconds as Nathan Tella netted with a calm finish between the legs of goalkeeper Steven Benda.
The turnaround was complete within nine minutes of falling behind when Nathan Redmond struck a low shot across Benda on 24 minutes, before Stuart Armstrong completed the scoring just shy of a raft of Saints substitutions on the hour.
Ralph Hasenhüttl named a much-changed side, with only Salisu and captain Oriol Romeu keeping their places from the starting line-up at Cardiff on Tuesday night, as regular skipper James Ward-Prowse remains sidelined by injury.
Saints started on the front foot, twice carving out chances from short corners taken by Redmond.
First, his cutback from the byeline fell invitingly for Moussa Djenepo, who was only denied a second goal in two games by a smart stop from Benda, who smothered the 20-yard shot low to his right.
Then Redmond picked out Romeu with a cross from the right, whose header down into the ground jumped up off a perfect pitch to send Benda flying in the opposite direction, high to his left, to keep Saints at bay.
Swansea had shown nothing as an attacking force but were gifted the lead on 15 minutes. Liam Cullen found space wide on the left and whipped in a cross inadvertently sliced into the top corner by the unfortunate Salisu.
The defender must have still been ruing his mistake when the net bulged at the other end, as Tella and Ché Adams renewed their partnership that put Cardiff to the sword.
This time Tella, who twice assisted his teammate in the capital, was on the scoresheet courtesy of a slick one-two and a cool finish, low between the legs of Benda, who was powerless to prevent an instant reply.
Saints were impressively unaffected by falling behind, with no let-up in their dominance.
After Stuart Armstrong, operating in a central role alongside Romeu, saw a goalbound shot blocked, Redmond completed the first-half turnaround as the visitors edged in front in the 24th minute.
Racing on to a through ball from Djenepo that split two defenders, he slotted a low shot into the far corner via a flick off the legs of Benda, who could not quite react quickly enough to the chance.
An enforced substitution for the Swans prompted a temporarily lull in an otherwise very watchable first half, in which Saints came close to scoring a third goal on two occasions in the closing stages.
First Adams showed a clean pair of heels to the last defender and fired the ball hard and low across goal, but just beyond Shane Long at the far post.
Long should have done better when picked out by Djenepo, who was having a good influence on the attack even from left-back, but the Irishman could not make a decent connection as he attempted to take the cross first time on the volley from eight yards.
Hasenhüttl opted to save Romeu’s legs at half-time, with the midfielder having played the full 90 minutes on Tuesday, so Ibrahima Diallo partnered Armstrong in the second half.
The boss made seven further changes on the hour, by which time Saints had extended their lead.
Scotland teammates Adams and Armstrong both steered shots just wide from the edge of the area, before Armstrong traded passes with Long, whose cutback was dispatched first time into the bottom corner with his left foot by the former Celtic man.
Saints had been remarkably comfortable throughout, and perhaps Alex McCarthy’s concentration was starting to wane was he caught in possession by Dan Williams, before Jan Bednarek saved his blushes with a timely clearance.
Swansea’s best move of the match arrived inside the final 20 minutes, when Liam Cullen’s disguised pass found Joel Piroe, whose intelligent cutback invited Jake Bidwell to shoot first time, but McCarthy was in the right place to make a fairly routine stop.
The closest Saints came to repeating their scoring exploits in Cardiff was a low drive from Mohamed Elyounoussi that was well held by Benda, but this time Hasenhüttl would have to settle for three.