It wasn't when he sprung off the wall with a near first-place start.
And it wasn't when he made a solid second-place finish.
It was when his head surfaced the water, he took off his goggles and smiled that Carolyn Grevers broke into hysterics -- a mixture of cheers and tears, as her younger brother won an Olympic silver medal.
"I hoped he'd take it, but I was most looking forward to his reaction after," Grevers said. "All I care about is that he is happy."
Lake Forest native Matt Grevers took a second-place finish in Monday night's Olympic 100-meter backstroke event, coming in behind U.S. teammate Aaron Peirsol at 53.11 seconds. Peirsol clocked 52.54 seconds.
Hundreds gathered at the downtown ESPN Zone for a party thrown by Grevers' siblings, Carolyn and Andy. Grevers' parents are in Beijing.