Rebecca Soni shook her fist. Then she did it again. And again. A U.S. star known for showing no emotion suddenly spilled it all over the pool. She had good reason: Soni not only won her second straight Olympic title in the 200-meter breaststroke Thursday night, she also broke her second world record in 24 hours and accomplished a long-held dream.

And there was this, too: She made up for the frustration of a second-place finish Tuesday in the 100 breaststroke, an event in which she is reigning world champion.

“That was the happiest” I’ve ever seen Soni, her coach Dave Salo said. “She was just ecstatic about it.”

There was, she figured, plenty to celebrate. She became the first 2008 Olympic gold medalist to repeat as champion at these Games, though Michael Phelps achieved a three-peat later Thursday, winning the 200 individual medley for the third time since 2004.

With her finish in 2 minutes 19.59 seconds, Soni, 25, easily held off Japan’s Satomi Suzuki, who finished in 2:20.72, and Russia’s Iuliia Efimova, who came home in 2:20.92.

“I’m so happy,” Soni said. “I didn’t try to focus on medals or records, I just wanted to swim one more race the way I knew I could. . . . I just wanted my hand on the wall. I was scared to look. I can’t believe it yet.”

Soni, a six-time NCAA champion while at the University of Southern California, had lowered the world record in Wednesday’s semifinals – going 0.01 seconds faster – but she hadn’t gotten under the 2:20 mark. That, she said, had been a burning personal goal dating back to her days at West Windsor-Plainsboro High School North in Plainsboro Township, N.J., simply because her coach then predicted she would be the first under that barrier.

“It’s been my goal since I was a little kid to swim under 2:20,” she said. “When my coach told me, ‘You’re going to be the first woman to go under 2:20,’ I’ve been chasing it ever since.”

Soni stood in second place after the first 50 Thursday night, but pulled ahead by the second turn. She flew home, covering the last 50 in 35.64 seconds, faster than her third 50 by 0.21 seconds.

Soni has a chance for another gold at these Games in the 4x100 medley relay, but she had hoped for three golds, not two. Tuesday, she was beaten to the wall by a 15-year-old phenom from Lithuania, Rūta Meilutytė.

“She was disappointed,” Salo said.

And ready to make up for it.

“She was cool and confident when she went off the blocks tonight,” he said. “This is her pride and joy.”