The attendance, 48,500, stood the test of time for decades and when clubs elsewhere began to catch up, the Welsh public turned out in sufficient force to keep pushing the record ever upwards, raising it to almost 55,000 for the Neath-Llanelli WRU Cup final in 1990.
Then the French and English took the figure to greater heights. Stade Francais began filling the Stade de France close to its 80,000-capacity for selected matches and Harlequins followed suit with their Boxing Day spectacular at Twickenham.
Not to be outdone, Ireland got in on the act with spectacular results. The Leinster-Munster Heineken Cup semi-final at Croke Park in 2009 created an all-time European record attendance of 82,208. While Saracens hoisted that figure to 84,000 last month, the Welsh have been busy reclaiming their support.
Judgement Day III, featuring the country's four regional teams in last Saturday's double header, drew almost 53,000 to the Millennium Stadium, a heartening leap from the 30,000 for the same event the previous year. It was, as WRU chairman Gareth Davies acknowledged, 'a fantastic event.'
The former Wales and Lions fly half, who began the season as chief executive of the Dragons before winning election to the Union, greeted the attendance as a measure of the recovery from the political wrangling of recent seasons.
In thanking the public for their support, Davies made no attempt to disguise his pride at an occasion which 'set both a Millennium Stadium record and a GUINNESS PRO12 record.'
Mark Davies, chief executive of the Regions' umbrella organisation, Pro Rugby Wales, described the huge public response as 'a clear illustration of what can be done when we are united and work as partners.'
The Ospreys revelled in the big-match atmosphere, hardly surprising given that players like Dan Biggar, Rhys Webb, Alun-Wyn Jones, Scott Baldwin and Justin Tipuric have been revelling in the Test arena all season.
The manner of their win over the Blues left no doubt about the Ospreys' right to be in the play-offs but their ability to reclaim a title they last won on Irish soil, against Leinster at the RDS Arena three years ago when Shane Williams scored in the last minute of his last match in the PRO12.
Of the top four, only Ulster failed to take all five points but their decisive home win over Leinster brought the champions' reign to a premature end. A run of five GUINNESS PRO12 matches without a win means that, for the first time since its creation six seasons ago, the most successful of all Irish teams in Europe will miss the Final.
Munster are one point above Ulster in second after making the most of Benetton Treviso's visit to Irish Independent Park in Cork. Whether Anthony Foley's men stay there and secure the priceless advantage of a home semi-final will be determined to a greater or lesser degree by the outcome of their next match - Ulster in Belfast on May 9.
It is just one of two monumental contests that weekend. Never before can the second last round of Guinness PRO12 matches have guaranteed a collision of the top four. As well as 2nd v 3rd in Belfast, 4th plays 1st in Swansea - proof that the PRO12 is the only League in Europe where the fixtures are drawn up by a team of clairvoyants.
The Warriors are still two points clear of the field but one defeat could drop them down to third, such is the intensity of the competition. Their next opponents may have swept all before them at the Liberty Stadium in the Guinness PRO12 this season but a win there on May 8 would secure the Glaswegians a semi-final in Glasgow.
Head coach Gregor Townsend will be all too aware that the Ospreys are running into their best form of the season at a time when it matters most. Their stylish double over the Blues, with ever-present full back Dan Evans bringing his try tally for the season to seven, sets them up for a monumental finale.
The Scarlets matched their local rivals try for try at the expense of the Dragons and in doing so stayed ahead in the three-cornered race to secure the last automatic qualifying place for the European Champions' Cup. Maximum points from their two remaining matches, at home to the Blues followed by Benetton Treviso in Italy, would ensure a top-six finish.
Edinburgh, one point behind the Scarlets, know they will almost certainly need a ten-out-of-ten finish, against the Dragons at Rodney Parade followed by Benetton Treviso at BT Murrayfield. Connacht, five points behind the Scarlets, need to pull themselves out of a four-match losing trot and hope their rivals stumble somewhere down the home straight.
Biggest attendances at Guinness PRO12 matches over the last four seasons (excluding Finals):
Date Match(es) Venue Crowd
Apr 25, 2015 Blues-Ospreys/Dragons-Scarlets Millennium Stadium 52,762
Mar 29, 2014 Leinster-Munster Aviva Stadium 51,700
Nov 11, 2011 Leinster-Munster Aviva Stadium 48,365
Oct 6, 2012 Leinster-Munster Aviva Stadium 46,280
Oct 3, 2014 Leinster-Munster Aviva Stadium 43,817
Mar 30, 2013 Blues-Ospreys/Dragons-Scarlets Millennium Stadium 36,174
Mar 31, 2012 Munster-Leinster Thomond Park 26,500
Dec 27, 2014 Munster-Leinster Thomond Park 25,600
Dec 29, 2012 Munster-Ulster Thomond Park 23,587
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