LONDON — Misty May-Treanor danced on the sand and then off it, leaving Horse Guards Parade with Kerri Walsh Jennings and a third gold medal.

Playing in the Summer Games together for the last time, the twice-defending champions extended their unbeaten streak to 21 in a row — through Athens, Beijing and now London — by defeating Jennifer Kessy and April Ross 21-16, 21-16 in an all-American final on Wednesday night.

The match started with nearby Big Ben pealing the hour and ended with the "Star-Spangled Banner" rising from the iconic venue in the Prime Minister's backyard, just down the Mall from the royal residence at Buckingham Palace. Playing on Henry VIII's former jousting tiltyard, with the current Prince Harry in the crowd, Walsh Jennings and May-Treanor continued their reign as champions of the beach.

"It's insane. It doesn't feel like it's real," Walsh Jennings said. "I told Misty when we were getting our medals: 'If I wake up tomorrow and we have to replay this match, I'm going to be furious.' Because it feels like I'm in a dream.

"It truly feels surreal and it didn't feel like that the first two times for whatever reason. But this, it's almost too good to be true."

Dominating the sport for three Olympiads, Walsh Jennings and May-Treanor have won every match they've ever played at the Summer Games and lost just one of 43 sets.

No one had ever won even two beach volleyball gold medals before the Americans won their second straight in Beijing.

No woman had ever won three Olympic beach volleyball medals of any kind.

"I know how hard it is to win one tournament. And the amount of tournaments they've won is crazy," said Kessy, who jumped for joy on the medal podium after she and Ross won silver in their Olympic debuts. "For them to do it for years and years and to be on top is just really impressive. We learn a lot from them."

Walsh Jennings and May-Treanor pulled away midway through the first set of the title match and were never threatened in the second, falling to their knees and hugging as Ross' serve went long on match point. Then they took the celebration to the stands, circling the stadium that was built on the 500-year-old parade grounds now used by the Queen's household cavalry.

Walsh Jennings covered her bare shoulders with an American flag and grabbed her children; the older one was a little scared. They high-fived the Horse Guards Parade Dance Team and volunteers and just about anyone holding an American flag.