LONDON – She's 16 years old, and for 50 meters on Saturday night, she swam faster than U.S. superstar Ryan Lochte. And now China's Ye Shiwen is at the center of some controversial buzz at the Aquatics Center of these Olympic Games.

Shiwen smashed the world record in the women's 400-meter IM and took gold Saturday night, torching the final 100 meters in the event and coming from behind to beat U.S. 400 IM champion Elizabeth Beisel. Shiwen shaved more than a second off Australian Stephanie Rice's world record in her win, finishing at 4:28.43. But it was her final 100 meters – the freestyle leg of the event – that raised eyebrows. Not only did Shiwen go virtually stroke-for-stroke with Lochte – who had won gold in the men's 400 IM earlier in the night – she beat Lochte in the final 50 meters.

Shiwen went 28.93 in her final 50 and 58.68 in her final 100 of her 400 IM. Lochte went 29.10 in his final 50. And the final 100 meters of the pair? Lochte went 58.65 to Shiwen's 58.68. That was such intriguing fodder that when Lochte was in the mixed zone Sunday morning, he said Shiwen had been a topic of conversation the previous night.

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"We were all talking about that at dinner last night," Lochte said. "It was pretty impressive. And it was a female. She's fast. If she was there with me, I don't know, she might have beat me."

Added U.S. men's swimming coach Gregg Troy, "Heck of a swim. You notice stuff like that... You guys can do the research. I think that's probably the fastest women's split ever."

By Sunday morning, most had noticed. The stunning final 100 meters had multiple swim insiders privately questioning how Shiwen could have beaten Lochte in the last 50 meters or managed a virtual dead heat in the last 100. Particularly in such a grueling race. The buzz was so prevalent, SwimmingWorldMagazine.com blasted those who had been speculating about Shiwen.

"It was going to happen," the magazine said in a piece Sunday morning. "It was only a matter of when, and with how much force. Not minutes after Chinese youngster Ye Shiwen captured the gold medal in the 400 individual medley on the opening night of Olympic competition, accusations started to fly. You know the type. She must be doping.

"What a bloody shame."

Shiwen wasn't among the race favorites, yet she effectively peaked in the 400 IM on the Olympic stage despite never having won the event in a long-course international event. She also had never won a medal at a world championships prior to taking gold in the 200 IM in 2011.

Afterward, she called her win "A big step for Chinese swimming."