In the red corner: A two-time Olympic gold medallist, the sport's biggest name over the last decade and a champion widely regarded as his sport's greatest of all time.
In the blue corner: A two-time runner-up, looking for redemption after the most trying year of his career, against a nemesis he had been broken by on this very stage twice before.
This was badminton, but the occasion also had all the ingredients of a big boxing fight. There was the fierce rivalry between Lin Dan - in red yesterday - and Lee Chong Wei, who was dressed in blue. There was their history at the Olympics. There was also the awareness that this was very likely the final clash between two greats on this stage.
The last time they met at the Olympics in 2012 ended with Malaysia's Lee crumbling to his knees, his face buried in his palms. The world No. 1 found himself in the same position yesterday - only this time, it was in victory.
After three tries at the Olympics, Lee finally got the better of Lin with a comeback 15-21, 21-11, 22-20 win, booking himself a spot in a third straight final.
This was not yet the win he craves the most. But it was celebrated like it was, for it was the first time he had beaten his rival at a major event.
Said the Malaysian, who had been denied two world and two Asian Games titles by Lin: "This is the first time that I've beaten him in a big competition. We both played a great match and I'm very proud to have won."
Lee, who for almost a decade had borne the burden of winning Malaysia's first Olympic gold, will meet China's Chen Long in the final today. The world No. 2 beat Dane Viktor Axelsen 21-14, 21-15.
Neither Lin nor Lee were at their best in the first two games, but finally gave the raucous crowd the contest they wanted in the decider.
Said Lin, a five-time world champion: "We're both not as young as we were before, but we played very high-level badminton today."
Down 17-20 in the rubber and just one point from defeat, Lin saved three match points - the last of which saw him almost losing his footing while scrambling from the back of the court to the net.
But a fourth match point ultimately proved one too many for the world No. 3 to save. It was reminiscent of the 2012 final, when Lee let slip a lead to give Lin the victory.
He admitted that he had flashbacks of that crushing defeat in the final points of yesterday's match.
Yesterday's victory was a big leap forward for Lee, who just a year ago was ranked No. 180 after a doping scandal. He tested positive for dexamethasone, an anti-inflammatory, at the World Championships and was handed a backdated eight-month suspension by the Badminton World Federation.
"It was not easy for me to come back from that. But the battle is not over yet. I have to put my focus on the final now," he said.
After the last point was played yesterday, with a respectful embrace, they exchanged shirts, perhaps knowing that their 37th meeting could also have been their last, and both should have something to remember it by.
Another person who will long remember yesterday is Carolina Marin. The Spanish world No. 1 captured her first Olympic title by beating India's P.V. Sindhu 19-21, 21-12, 21-15.