Doubt cast over 'unbelievable' displays by China prodigy Ye Shiwen

China’s Ye Shiwen shows the power in the freestyle that took the 16-year-old to another record yesterday (AFP)

London 2012 has been forecast as the women's Games. In the Aquatics Centre it has become the young women's Games. Last night, as 15-year-old Ruta Meilutyte came out at one end of the stadium to receive her gold medal, Ye Shiwen, her senior by a year, was retreating out the other with another record to her name.

The Chinese swimmer has become a controversial figure in the wake of her world record-breaking victory in the 400m individual medley on opening night on Saturday. Yesterday the influential American coach John Leonard, the executive director of the World Swimming Coaches Association, labelled that performance as "unbelievable" and then pointed out carefully that he meant that in the truest sense of the word.

Ye won the World Championships in Shanghai in the 200m individual medley last year but it is her split times that have attracted particular attention – her final 50m on Saturday was quicker than Ryan Lochte recorded in the men's event. Last night she produced another devastating final length of freestyle, covering it in 30.59sec, a new Olympic record.

That was two seconds short of Ariana Kukors' world record, set at the height of the controversial body suits at the 2009 World Championships. It is in danger tonight and there seems little to prevent her claiming a second Olympic gold.

There was a first gold for Missy Franklin, the grand dame of the three at 17. Franklin snatched gold at the last from Emily Seebohm of Australia, who had set an Olympic record in winning the morning's semi-finals.

"It is exceeding the expectations one hundred billion times over," said Franklin of the first of what should be a sizeable golden collection.

With a bronze and now a gold to her name, Franklin has another five events. It is a punishing schedule – her final last night came just 20 minutes after she had negotiated the semi-finals of the 200m freestyle.