Alun Wyn Jones gave 6,238 fans a night to remember as he featured for both sides in Barbarians' 68-33 win over Swansea.
Three days on from his maiden Barbarians appearance against a World XV at Twickenham, Jones represented the Baa-Baas in the first half before donning the Swansea shirt after the restart, at the venue where he made his club debut against Carmarthen Quins 19 years ago.
The star-studded event saw the 37-year-old wear the Barbarians jersey for the final stages on what was a night to remember for the world's most-capped international.
The All Whites - celebrating their 150th anniversary - were full of confidence early on.
But Barbarians wasted no time in showing their superiority as Olly Robinson, Stephen Shingler and Taichi Takahashi all touched down inside the opening 15 minutes.
The bumper crowd - which included legendary Wales and British and Irish Lions prop Adam Jones, and ex-Wales fly-half James Hook - were on their feet midway through the first half as Swansea turned on the style to score their first points with a try from Joe Thomas.
John Mulvihill's side responded with a sublime score of their own through Tom Howe, before Hanno Dirksen hit back with another try for the hosts.
Howe notched his second try of the game in the final stages of the first half, which was played in jovial mood throughout, and typified by the celebrations of Bradley Davies - on his final career appearance - who raised his fist into the hot Swansea air upon hearing the stadium announcer's confirmation that beer tents had been replenished with stock ahead of half-time.
Jones re-emerged from the dressing room in the white jersey of Swansea, much to the delight of the crowd in attendance.
It ensured he was on the receiving end of Barbarians' quality in the second half as Damien Hoyland and Shingler both crossed the whitewash shortly after the restart.
Former Cardiff, Wasps and Ospreys lock Davies enjoyed his moment in the limelight by converting Rey Lee-Lo's try for the Baa-Baas.
On 52 minutes, St Helen's united in applauding Jones off the field as he prepared to watch the final stages from the comfort of the dugout.
Kirby Myhill notched Barbarians' ninth try before Brandon Wood, Matthew Aubrey and Willis Wood responded with efforts for Swansea.
Jones, on his homecoming, received another round of rapturous applause as he donned the Baa-Baas shirt for the final throes of the contest which ended with Myhill scoring his second try of the game, and Tonga international Elvis Taione amusing the crowd before adding the conversion.
Jones with 'a tear in his eye'
Davies admitted his fellow second row Jones had a tear in his eye after being caught up with the emotion of the 15-try thriller in Swansea.
"Alun Wyn's a fantastic player, he's had an amazing career and no one will ever achieve what he has," said Davies.
"It's mad because we were probably fighting for the same shirt for 15 years - he's taken about 200 caps off me!
"He's a good mate of mine and you can see what it means to him.
"Before the game he was upset, with a tear in his eye. He's a very passionate man but it was nice to see him have a proper send-off."
Davies stole the limelight late on as he converted a try just three days after Jones was unsuccessful from the kicking tee during Barbarians' dramatic 48-42 win over a World XV at Twickenham.
"We said all of the boys leaving had to have a shot," added Davies.
"I picked it tactically, as soon as there was one in front of the posts, I took the first one. As long as I beat Alun Wyn, I'm happy."
Davies added: "Rocking up here to St Helen's, full, with the crowd on the bank, a nice day - these are my memories of Welsh rugby.
"It was 100% a throwback. That's what we're missing. I'd watch Pontypridd versus Cardiff on Boxing Day any day of the week.
"We had more than 6,000 here today, a great family occasion. That's what we miss."
Swansea: Gareth O Rees; Brandon Wood, Joe Thomas, Osian Knott, Matthew Jenkins; James Davies, Gareth J Rees; Tom Sloane (C), Owen Thomas, Richard Murphy, Lloyd Ashley, Matt Dodd, Jay Williams, Callum Bowden, Joe Greaves.
Replacements: Garan Williams, Ed Thompson, Scott Jenkins, Chris Thompson, Sam Richards, Matthew Aubrey, Chris Morgans, Willis Wood, Hanno Dirksen, Tom Crockett.
Barbarians: Damien Hoyland; Taichi Takahashi, Rey Lee-Lo, Billy Twelvetrees, Alex Wootton; Stephen Shingler, Lewis Jones; Oli Kebble, Kirby Myhill, Enrique Pieretto, Bradley Davies, Alun Wyn Jones (C), Dan Lydiate, Olly Robinson, Sione Vailanu.
Replacements: Elvis Taione, D'Arcy Rae, Murray McCallum, Matthew Screech, Sam Cross, Harri Morgan, Lloyd Williams, Billy Searle, Tom Howe.