France's Leon Marchand won a sensational fourth Olympic gold in the Paris pool, beating Duncan Scott into second place, moments after Ben Proud also won a superb silver for Team Great Britain.
With French President Emmanuel Macron in the crowd, home superstar Marchand led from the start of the 200m medley to cap a sensational week for the 22-year-old.
He emerged from the pool to an almighty roar, having become the first swimmer since US legend Michael Phelps to win four individual golds at one Games.
Scott, 27, was second behind the Frenchman - just as he was at last year's World Championships - and took silver for the sixth time in his career, and an eighth Olympic medal overall. Britain's Tom Dean was fifth.
Earlier, fellow Englishman Proud ended his long wait for an Olympic medal by claiming silver in the 50m freestyle.
At his third Olympics, 29-year-old Proud - who had won world, European and Commonwealth gold but never a medal on the
sport's biggest stage - was second, just 0.05 seconds behind Australia's Cam McEvoy in the one-length sprint.
France's Florent Manaudou took bronze, which only ramped up the atmosphere for Marchand to enjoy more glory at the Games.
Despite pressure from Scott down the final leg, one of the poster boys of Paris 2024 proved too strong - as he has in all of his four finals this week - to complete one of the great achievements in recent Olympic history.
He now holds the 200m and 400m medley titles, as well as the 200m butterfly and breaststroke golds which were won in one session on Wednesday.
Perhaps, though, his remarkable achievement is best summed up by the fact he would be 10th in the medal table on his own.
Only three other people - Phelps, fellow American icon Mark Spitz, and Kristen Otto, who won four golds for East Germany - have won four or more individual swimming medals at an Olympics.
That is the company with whom Marchand, seen as the successor to Phelps and coached by the US great's former mentor Bob Bowman, now sits. His races this week have been the most sought-after tickets and the atmospheres the loudest, since an Antoine Dupont-inspired rugby sevens side won gold for the hosts at least.
His win was rarely in doubt, missing out on Ryan Lochte's world record mark by 0.06 seconds.
When he saluted the crowd after holding up four fingers he
received a thumbs-up from Macron, who had just leapt from his seat in celebration.
Marchand's time of one minute 54.06 seconds was an Olympic record, breaking Phelps' mark in 2008, and a third in his past three finals.
"The guy is a machine," said BBC commentator and former Olympian Andy Jameson.
Rebecca Adlington, 2008 double Olympic champion for Team GB, said: "After doing two in one night this probably felt at ease. It was fantastic."
