Swansea City are officially in the history books.
Russell Martin's men thumped their local rivals Cardiff City 4-0 in the capital to become the first ever side to achieve the double in the South Wales derby. You can read the match report in full here.
Here are the key talking points to emerge from the emphatic win over the Bluebirds.
Obafemi's remarkable turnaround explained
Michael Obafemi struck the first and final blows in what was a memorable day for Swansea in Cardiff.
The Republic of Ireland international tapped home after just six minutes before completing his side's 4-0 rout with a cool curling finish late on to cap off a special afternoon for the Jack Army. The striker's latest brace - his third of the campaign - means he has scored eight goals in his last 11 outings having only netted once in his first 14 appearances for the club.
It represents an astonishing turnaround for a player who was dropped from the matchday squad altogether when Swansea were beaten 4-0 by Bournemouth in November. And head coach Martin has explained the reasons behind the 21-year-old's dramatic upturn in form.
"I put it down to finding a level of consistency in his daily approach and his willingness to accept criticism and be honest with me and his team-mates. Most of all, he's dropped his guard and is being himself," said Martin.
"He's just worked really hard, good attitude and the rest comes. We've said that to him all the way along. He's showing glimpses of his potential and hopefully he'll become a really big player for us.
"It wasn't easy for him to come in and settle but for him to be doing what he's doing is nice to see. I'm really proud of him because he's come a long way on and off the pitch and he needs to continue growing like the rest of the young guys do with us. I'm sure he'll be the first to praise his team-mates and the role they've played. He's been brilliant."
Cabango one of Martin's 'favourites'
Ben Cabango showed immense composure as he rifled beyond Alex Smithies to extend Swansea's lead during the South Wales derby.
It was the Welshman's second goal of the campaign and his first in the Championship since netting the winner against Coventry City on February 24 last year. As for his defensive duties, Cabango more than played his part in helping the Swans keep their 15th league clean sheet of the season.
The 21-year-old made five clearances and won three aerial duels against Cardiff and was pivotal in ensuring the likes of Jordan Hugill and substitute Uche Ikpeazu failed to trouble Andy Fisher. His sublime strike against the Bluebirds came just nine days after he was omitted from Wales' matchday 23 to face Austria in the World Cup play-off semi-final at the same venue.
And Martin believes Cabango has all of the tools in his armoury to play at the highest level in the game. "Ben's one of my favourite players I've ever worked with in terms of his attitude, willingness to work and do extra," said the Swansea head coach.
"If you look at Ben at the start of the season to now and how much he's grown in possession and as a defender, it's incredible. He was really disappointed not to be in the squad for the big game last week. He responded well by putting in a really good performance against Czech Republic.
"If he keeps having days like this with us and keeps growing, he has a big future for club and country. He has every attribute he needs to play at the top level, in my opinion. Hopefully that will be with us, that would be the best thing ever that some of these young guys grow with us and we all get there together. That would be amazing.
"He just needs to keep doing what he's doing. You'll see it in the dressing room with how much he's respected by his team-mates and how much they love him. Thankfully his hard work is paying off."
Read more: Russell Martin blown away by Swansea City celebrations as special pre-match video emerges
Here's to you, Russell Martin
If ever proof was needed as to why Swansea appointed Russell Martin as their head coach, this was it.
The 2021/22 campaign has been somewhat difficult for the Swansea faithful to follow due to the inconsistency of performances. Highs have so often been followed by lows while eye-catching moments of play have been accompanied by patches that set the alarm bells ringing.
In short, it's exactly what Martin promised from the outset and the reason why the need for patience has so often been preached. From the very beginning, the former Scotland international said there would be pain in his debut campaign at the club.
The club are no longer receiving parachute payments and revenues have taken a significant hit owing to the coronavirus pandemic. It has all ensured the purse strings at the Swansea.com Stadium are tighter than they have been for a long time.
The remit has been to produce assets while also transforming the club's playing style. In that regard, two boxes can be ticked.
The transfer values of young guns including Joel Piroe, Ben Cabango, Michael Obafemi and Flynn Downes have undoubtedly increased this term while the tactical shift from the previous regime has been there for all to see ever since the opening day contest with Blackburn Rovers at Ewood Park.
At Cardiff, Swansea showed all of the composure, courage and belief their boss asked them to. Time and time again, those kitted out in all white played bold passes, took risky options and, crucially, executed their actions to perfection to ensure they could pull apart their meek neighbours.
The summer transfer window will go a long way to determining whether or not Swansea can seriously challenge for a top six place in the Championship next season. But in Martin, the Swans have found themselves a man who has implemented methods that will give them a real chance of doing something special in the near future.
Who was your man-of-the-match from the South Wales derby? Have your say in the comments section below.
Ntcham update
Olivier Ntcham missed Swansea's win over Cardiff due to illness.
The 26-year-old was expected to be listed among the substitutes for the clash with Steve Morison's side having been away with Cameroon during the international break. However, he was not included in the Swans' 18-man squad for the triumph against the Bluebirds.
He will be assessed ahead of Tuesday night's trip to Millwall.