Minutes after Chad le Clos did the unthinkable on Tuesday night and out-swam a man who, minutes later, confirmed his status as the greatest of all Olympians, his rather less athletic father went one better and managed to upstage them both.
Bert le Clos looked as if he might explode when his boy beat Michael Phelps by a fingernail in the 200m butterfly final, but it was in a post-race interview with the BBC that the South African revealed what sport can do to an Olympic parent.
"Unbelievable, unbelievable, unbelievable!" he told Clare Balding as his son's victory was replayed on screens in the Aquatics Centre. "Look at him, he's beautiful, I love you." When his own image flashed on to the screen, Le Clos asked whether the interview was being broadcast live. "I have never been so happy in my life," he added. "It's like I have died and gone to heaven."
Behind the emotions of the athletes, in these Olympics we have watched a greater range in the faces and contortions of their mothers and fathers, who have provided some of the most touching scenes of the Games. Television directors have become wise to the goldmine in the stands, zooming in on relatives to show what all the sacrifice and expectation can mean when it's your boy or girl performing down there.
When the US gymnast Aly Raisman swung and leapt about the uneven bars on Sunday night, her parents went through a routine in the stands that looked almost as physically draining. Lynn and Rick wriggled and writhed in a clip, left, that has now gone viral, mirroring Aly while shouting: "Stick it, please. Stick it!" When she does stick it, they punch the air, realise where they are and collapse, exhausted. "We know how long and how hard she's worked, literally every day for the past 15 years," Rick said the day after.
Parents can provide emotional bridges between superhuman athlete and the mortal viewer at home. It takes something special to compete at the Olympics, but mums, dads, sisters and brothers have day jobs. They're like us, their own sacrifices notwithstanding, but for a few seconds beside a pool or a pommel horse, they must go through hell, powerless to help their offspring. It's like seeing off your child on their first day of school when, seconds later, school has the power to change everything.
There are cooler observers, of course. One does not holler when one's daughter is on her horse, though the Princess Royal did beam as she presented Zara Phillips with a silver medal and a hug (below) on Tuesday. The pushiest parents, meanwhile, will not always be pleased. "We expected gold but it is a very good achievement," said BS Narang, the father of Gagan Narang, who came third in the 10m air-rifle final on Monday.
Bert le Clos was wonderful, but it's unlikely a parent will ever create sporting drama as heart-wrenching as that which unfolded at the 1992 Barcelona Games. When British favourite Derek Redmond's hamstring snapped on the back straight in a 400m semi-final, he picked himself up, determined to hobble to the line. Terrified his son would make his injury worse, Jim Redmond fought his way on to the track to stand by his son. Derek stopped and wailed on his father's shoulder. And then they finished together, father supporting son in a way few Olympic parents will ever manage to do, and 80,000 people cheered through tears. If you haven't already done so, watch it and weep: ind.pn/redmonddad.