Chinese teenager swimmer Sun Yang, winner of the men's 800m freestyle at the Shanghai worlds, breezed into the 1500m free final?in Shanghai?on Saturday.

The 19-year-old Sun, who was only 0.87 second off Grant Hackett's 2001 world record in the men's 1,500m freestyle at the Asian Games in last November, expects to set a new record here.

China are second behind the United States at the top of the swimming medals table in Shanghai as the hosts claimed four golds till Saturday morning. And Sun looks a viertual certainty to win Sunday's 1500m free final.

Sun led the heats in 14:48.13, followed by Gergo Kis of Hungary at 14:52.72. Peter Vanderkaay of the United States clocked the third fastest time in 14:54.99.

"It's an easy race this morning. As for the final, I hope I can do my best and surprise everybody, but nobody knows what will happen," said Sun.

Jessica Hardy of the United States was the fastest qualifier in two events. Hardy and Therese Alshammar of Sweden tied for the leading time in the women's 50m freestyle heats before Hardy returned to top the 50m breaststroke heats.

Her compatriot Rececca Soni qualified joint second quickest for the semifinals of the 50m breaststroke in 30.72 with Russian Yuliya Efimova as she seeks a third title after winning the 100m and 200m.

In the men's 50m backstroke heats, South African Gerhard Zandberg led the heats in 24.72, while French Camille Lacourt was the second and German Helge Meeuw was third.

British world record holder Liam Tancock also reached the semifinal, qualifying joint 10th fastest in the heats.

Elsewhere, the United States easily advanced in the women's 4x100m medley relay heats with the top time of 3:56.95. Russia was second at 3:59.08, followed by defending champion China at 3:59.44.