Against the odds, the star-studded Ospreys are toiling to get the better of the Border Reivers, playing their last-ever game before they are put out of business. Deep in the second half, the Ospreys have a title on the line, needing victory to edge ahead of their rivals Cardiff Blues.
Then an extraordinary thing happens. With a few minutes left on the clock, Gregor Townsend, the Reivers fly-half, is replaced by Steve Jones. Townsend has already announced that this will be his final game of rugby, and as he trots towards the touchline the crowd rises to bid farewell.
Predictable enough but, astonishingly, the Ospreys players join in the applause as well. In such tense circumstances, it is a remarkable display of sportsmanship.
"I had forgotten about that," said Townsend yesterday when the incident was recalled. His amnesia was convenient, but it did beg the question of whether his Glasgow players would cheer Brian O'Driscoll off the pitch if the great Irish centre, in his swansong performance, makes an early exit as well.
"I think they will be focused on the game," Townsend replied. "In any case, I think Brian will be there right to the end, putting in the tackles and challenging at the rucks as he has done for the past 10 to 15 years."
For the most part, Glasgow players and officials have ducked questions about the emotional impact of O'Driscoll's going. Their reluctance to get involved in the issue is understandable, but there is no question that the departure of the world's most-capped player will add a charge of high emotion to tonight's game. But will that factor energise Leinster or inhibit them? Perhaps a bit of both.
"It can have an effect," Townsend acknowledged. "But playing in a final you are going to bring lots of energy anyway. There will be 20,000 people there, whether a player is retiring or not.
"It is fantastic that we are involved in Brian O'Driscoll's last game. He has been one of the best players in world rugby over the past 10 years, a leading figure in the northern hemisphere alongside Jonny Wilkinson.
"So we are delighted to be in a final, delighted to be involved in that game. But it's 80 minutes of tough rugby and he will be one of the contributors to that game."
Has the O'Driscoll factor dominated discussions at Glasgow? "Certainly not this week," Townsend replied. "I mentioned him last week, mentioned the emotion of the game from their perspective. But we also have three players who will be playing the final games for the club. It is important for our team to get behind them just as Leinster get behind Leo Cullen [who is also retiring] and O'Driscoll."
Stripped of such inconvenient subtexts as O'Driscoll and Leinster's overwhelming advantage in terms of experience, Glasgow might go into tonight's game as slight favourites on the strength of the remarkable nine-game winning streak that has brought them to where they are today.
The past two months and more have been a period of intense focus and unwavering success for Townsend's side. It has also been a period in which the attacking sharpness that was so elusive earlier in the season has returned in thrilling fashion, but only a fool would expect a hatful of tries from either side at the RDS this evening.
Glasgow's magnificently stern semi-final victory over Munster, and Leinster's equally gritty win against Ulster the following day, have set a more likely tone. Glasgow go into the final boasting the best defensive record in the PRO12 for the third successive season, a remarkable record and a glowing tribute to defence coach Matt Taylor.
Discounting the bizarre ding-dong of their 37-34 win over Edinburgh last month, only one other side has scored more than 25 points against them in the PRO12 this season. The name of that side was Leinster. And yet, games between Glasgow and Leinster have been fiendishly close in recent seasons. You have to go back to the 2010-11 campaign to find a league match involving the two sides that was settled by a margin greater than a converted try. But it is just as striking a statistic that Glasgow have won just once in their past 19 visits to Dublin.
Having two weeks between the Munster semi and the final has allowed Townsend to discount fatigue as a selection criterion. However, the nature of their win over Munster is probably an even greater luxury, and he has recognised that performance by making just two changes to his starting lineup, a stark contrast to his practice of making sweeping alterations even when his side has been winning.
The changes see Peter Horne and Gordon Reid come in at the expense of Mark Bennett and Ryan Grant respectively. Horne, Townsend explained, offered more options as a second receiver and a left-footed kicker, as well as his pleasing habit of playing particularly well against Leinster.
Reid, frankly, made himself undropable with his try-scoring performance after he replaced Grant in the Munster game.
So the starting XV forms up along expected lines. Yet Townsend admitted that the process had not been easy.
"We have a lot of players back from injury and training and it hurts me that they cannot play in the final," he said. "It will be nothing like the hurt they feel, but I have to say they have all been very professional and are fully behind the team. The semi-final win, and hopefully the final win, is as much theirs as the 15 on the field.
"This is when the players take over. We had a great meeting this morning; they have set their goals and we have talked about what we expect from Leinster based on our experiences in previous semi-finals against them.
"I'm expecting a really big performance from Leinster. We have to be very switched on at the contact area. For years they were the role models and creating quick ball and disrupting your ball. I'm sure they expect a battle there, but we are up for it."