The day began with controversy when a Canadian horse was disqualified by veterinarians, leaving Canada without a drop score in the competition where the best three scores out of four riders count.
Gymnastics. This time, a tiebreak cost Louis Smith even more.
Four years after he dropped from second to bronze in pommel horse, a tiebreak got the British gymnast again, giving him silver instead of gold.
He and Hungary's Krisztian Berki finished with identical 16.066 scores, but Berki got the gold because his execution score of 9.166 was .10 points better. With the Duchess of Cambridge, the former Kate Middleton, sitting in the front row, just a few feet away from him, Smith stared at the scoreboard with a look of astonishment.
Still, it wasn't a bad day for the British. Four years after Smith gave them their first individual gymnastics medal in a century, they got another - two, actually, with Max Whitlock taking the bronze. As the two left the arena, Smith flashed a "V for victory" sign at a TV camera.
Earlier Sunday, American McKayla Maroney's rare mistake cost her a gold medal on vault that was all but hers. Maroney appeared to land her second vault on the backs of her heels. Her feet slid out from under her, and she plopped on the mat, a look of shock crossing her face.
"I already knew that I pretty much only had the silver medal. I really didn't deserve to win a gold medal if I fall on my butt," Maroney said. "I was still happy with a silver, but it's still just sad."
Sandra Izbasa of Romania won the gold. Also, Zou Kai won his fifth career gold medal, defending his title on floor exercise.
Boxing. Siarhei Karneyeu lingered in the ring after his Olympic heavyweight loss, crying and shaking his head in disbelief after his clutching, holding opponent got a narrow victory.
When Cuba's Jose Larduet fell victim to a similar decision about 15 minutes later, the Belarusian came back up the fighters' tunnel and intercepted Larduet on the way out of the ring, holding up Larduet's hand as the real winner.
Both Karneyeu and Larduet felt cheated by their opponents' clutch-and-grab tactics in the Olympic boxing tournament Sunday night, but amateur boxing's governing body disagreed.
After Belarus and Cuba immediately protested the losses, AIBA swiftly conducted reviews Sunday night, rejecting both protests about 90 minutes after the last bout.
Volleyball. Destinee Hooker scored 19 points as the undefeated U.S. women's volleyball team wrapped up preliminary pool play at the London Olympics with a straight-set victory over Turkey.
But the top-ranked U.S. team was hurt in the third set when captain and three-time Olympian Lindsey Berg injured her left ankle.
Foluke Akinradewo added 15 points in the 27-25, 25-16, 25-19 victory for the Americans, who had clinched the top seed in their pool for Tuesday's quarterfinals.