|Six Nations: Wales v Ireland|
|Venue: Principality Stadium, Cardiff Date: Saturday, 16 March Kick-off: 14:45 GMT|
|Coverage: Live on BBC One and S4C, BBC Radio 5 Live, BBC Radio Wales, BBC Radio Cymru and BBC Sport website and BBC Sport app, plus live text commentary.|
Wales versus Ireland in Cardiff. One team vying for a Grand Slam, the defending champions standing in their way. An epic Six Nations finale lies in wait. And we've been here before.
The state of play at the Principality Stadium on Saturday will be as it was 10 years ago. The difference between now and 2009 is that the roles will be reversed.
This weekend, Wales are bidding for a first Grand Slam since 2012, taking on an Irish side who managed the feat last year and still have hope of retaining their Six Nations title.
A decade ago, it was the other way round. Ireland were looking to end a 61-year wait for a Grand Slam, faced with a Welsh team who had completed the clean sweep 12 months earlier but needed to beat their opponents by 13 points or more to retain their crown.
- Six Nations set for grandstand finish
- Wales' Grand Slam glory days
- 'Stitches, finding form and renewing rivalries'
- Irish eyes not always smiling in Cardiff
For Wales, winning a third title in five would have been significant enough. Denying their Irish rivals a historic moment of glory would have made it all the sweeter.
These two sides, you see, did not much like each other.
But did the Celtic cousins not stick together? Not as far as Wales' head coach Warren Gatland was concerned.
"Probably, out of all the teams in the Six Nations, the Welsh players dislike the Irish the most," he said before their 2009 clash.
On the field at least, the enmity was mutual, as Ireland's blindside flanker that day, Stephen Ferris, explains.
"Off the pitch the lads get on so well, like on the 2009 Lions tour. Andy Powell, Mike Phillips, Shane Williams, James Hook - they're all really good lads and we had a really good bond," Ferris says.
"But when it comes to that whistle being blown, all hell breaks loose.
"They both do everything to win. You know fire is going to meet fire."
When fire met fire
That was certainly the case in a full-blooded start to the match 10 years ago.
It took less than a minute for Donncha O'Callaghan to spark the first scuffle with Ryan Jones, while Ian Gough floored Jerry Flannery with a shuddering hit.
All this - and a match-ending injury for Ferris - in less than five minutes.
"If anyone ever says dive on a loose ball, don't. Just stick your foot in there like Martyn Williams," Ferris recalls with a laugh, albeit still with a little wince.
"His foot caught my finger and I had a compound dislocation. I remember waving at [referee] Wayne Barnes and saying 'My finger's sticking out' but he just waved play on.
"I got stitched up and was about to get back on but the doctors said there was a risk of getting an infection, so they didn't let me back on and I just burst into tears.
"It was the biggest game I'd ever played in and having to go off was devastating.
"I stayed in the changing room feeling sorry for myself for a bit but then I got back out and got behind the lads."
It was an animated Irish bench watching on during an engrossing, tight encounter, which Wales led 6-0 at half-time thanks to two penalties from Stephen Jones.
Ireland did not panic. They started the second half purposefully, immediately pinning Wales back with a period of concerted pressure.
Wales defended stoically but Ireland were patient, accurate, relentless.
Wave upon wave of attacking phases eventually led to the opening try, from a familiar source but in unfamiliar fashion as their talismanic centre Brian O'Driscoll - more renowned for virtuoso solo scores - burrowed his way over the line like a gnarly old prop.
That came in the 44th minute and, just 120 seconds later, Ireland had a second try.
From a scrum 10 metres inside the visitors' half, Ronan O'Gara delicately clipped a kick out to the right, towards Ireland's onrushing wing, Tommy Bowe.
"It was a great kick by Ronan and the ball bounced nicely for me," said Bowe.
"Luckily enough, it bounced between Shane [Williams] and Gav [Henson], and I was able to just snatch it and make it between the posts. There was a great bunch of Irish supporters there.
"It was a special day, a special occasion and very special for me to score a try."
It was a finish befitting a match of this magnitude; beating a wing as quick as Williams for pace was no mean feat.
That Williams and Henson were both team-mates of Bowe's at Welsh regional side Ospreys made the score even better.
Ireland now led 14-6 but still with more than half an hour left to play.
Wales were not going to relinquish their Six Nations title lightly and another two Jones penalties brought them to within two points of their opponents.
Then, with only five minutes left, Jones struck a drop-goal to put the hosts back in front and set up a nerve-shredding finish.
"I can safely say I've never been involved in such an emotional and dramatic last five minutes," Jones said in the immediate aftermath.
The Welsh fly-half epitomised the game's wild swings in momentum as much as anybody. Seconds after putting his side 15-14 up, Jones misplaced a clearance straight into touch and handed Ireland a prime attacking platform in their opponents' 22.
They exploited that lapse with another assault on the Welsh line, setting up O'Gara for a drop-goal of his own, which he stroked over to prompt a huge roar from the Irish contingent in Cardiff.
"Every time we played Ireland, before the game we'd talk about Ronan O'Gara because he was a special player," recalls Shane Williams, who could only watch from the left wing as the kick sailed over.
"You could target him [in defence] but, with ball in hand, you knew he could kick it from anywhere on the field. So for him to do that, he was a hero for Ireland.
"He broke our hearts. That's what the best players in the world can do."
With only a little over two minutes left on the clock, Ireland seemed to have finally secured that elusive Grand Slam.
And yet, there was still time for even more drama.
Wales regained possession from the restart but struggled to force their way into Ireland's half and penalty range.
Ireland just had to keep their discipline and a first Grand Slam since 1948 would be theirs.
But then as the match entered its final 60 seconds, Irish replacement Paddy Wallace - who had only been on the field for three minutes - entered a ruck from the side and conceded a penalty.
"I was in a state of shock," Wallace said.
"The only thing I can compare it to was being in a car crash - which I had experienced before - and the numbness I got after the incident.
"I closed my eyes and thought our championship was over.
"I knew my life would never be the same again should it go over."
Just a couple of yards inside the Ireland half, this was a difficult kick.
Henson would usually have stepped up from such a distance but, after missing a kick from the halfway line earlier, the Ospreys centre had supposedly complained of back pain and left the penalty for Jones.
"I was happy to take it, fatigued though I was, because I knew it was in my range," Jones said at the time.
This would be the final action of the match, and the British and Irish Lion struck the ball well - but not well enough.
It fell just short and into the arms of another Irish replacement, Geordan Murphy, who gleefully kicked the ball into touch to end the game.
Wallace was off the hook.
"Relief, elation, 61 years of waiting for an Irish Grand Slam win were over," he said. "Just."
'The whole range of emotions'
Ireland were euphoric and yet, even as they celebrated such a momentous achievement, their match-winner O'Gara sought out his opposite number Jones for a commiserating embrace.
"I experienced the whole range of emotions from when my drop-goal went over right up to the final kick to win the game. It was mad," said Jones.
"It was bitterly disappointing."
Even if Jones' penalty had gone over, Ireland would have won the title on points difference - but this was a case of all or nothing.
As their captain and man of the match O'Driscoll said afterwards, anything other than a Grand Slam would have been "heartbreak".
An exhausted puff of his cheeks and raising of his arms at the final whistle said as much, embodying his nation's sense of catharsis after 61 years of hurt.
The wait was not quite as long for Ireland's next Grand Slam, which came last year.
And this Saturday it will be Wales - on a record 13-match winning run - aiming to clinch their first clean sweep since 2012.
Williams was a member of Wales' Grand Slam-winning sides of 2005 and 2008, the first of which was secured with victory over Ireland in Cardiff on the final weekend.
But having also played in the tumultuous defeat of 2009, he knows better than most why Wales must be wary of Ireland this weekend.
"Ireland will come here to spoil Wales' party," he says.
"They also still have a chance of winning the competition. Ireland were disappointed with the way they started, losing to England, particularly after beating New Zealand in the autumn.
"So they'll have a point to prove. I don't like to say it but they know how to win in Cardiff."