Chinese teenager Sun Yang toppled swimming's oldest world record yesterday when he shattered Grant Hackett's 10-year mark in the men's 1500m, ensuring a rousing finish to the Shanghai world championships. Sun, roared on by a capacity crowd, put on a devastating burst over the last 100 metres as he made up a deficit of more than two seconds to touch in 14min 34.14sec, 0.42sec inside Hackett's mark set at the 2001 meeting in Fukuoka. America's Ryan Lochte claimed a superb fifth gold medal, and stuttering Olympic great Michael Phelps enjoyed a successful final night when he helped the United States defend their 4x100m medley title. Sun's performance was only the second new record in Shanghai, two years after polyurethane-clad swimmers set 43 new bests at the 2009 championships in Rome. It broke the only men's mark to survive the infamous super-suits era, when muscle-compressing swimwear helped set more than 200 global bests in just two years. I was not obsessed with the world record before the final, because I wanted to focus on my plan-my goal was to win the gold," Sun said. "I'm so grateful to the whole Chinese team, including my coach and my parents as well, and I think the world record belongs to all of them." Meanwhile US star Lochte, this week's other record-setter, underlined his supremacy in Shanghai with his fifth gold medal, matching Phelps' haul from 2009. Lochte led from start to finish at the Sea Crown stadium to defend his 2009 title in 4min 7.13sec, more than four seconds ahead of team-mate Tyler Clary with Japan's Yuya Horihata third. But Lochte insisted he was "not really happy", saying he could still make big improvements before next year's London Olympics. For the most part I'm not really happy. I mean getting five gold medals is definitely great but the times I went I know I can go a lot faster," he said. There's a lot of places in my races that I messed up on, where I could have changed and would have gone faster but I guess I have a whole another year to make sure I have those perfect swims. Also on the final night, American world record-holder Jessica Hardy made a successful return to the world stage from a doping ban when she won the 50m breaststroke ahead of defending champion Yuliya Efimova of Russia. Hardy, who missed the 2008 Olympics after a positive test and was serving a one-year ban during the 2009 world championships, timed 30.19sec-outside her record of 29.80 -- with team-mate Rebecca Soni third. I am really excited, I've trained so hard for that," Hardy said. I am really, really glad that I did it. I performed very well. All of us did a good job. British world record-holder Liam Tancock defended his 50m backstroke title from France's Camille Lacourt and Gerhard Zandberg of South Africa. Sweden's Therese Alshammar won the women's 50m freestyle and America's Elizabeth Beisel won the 400m individual medley. And Phelps was instrumental in the United States' 4x100m medley win, as he took them from fourth to second in the butterfly leg before Nathan Adrian finished off the win. Lochte has long played second fiddle to Phelps but he has called the tune in Shanghai, beating his contemporary in the 200m freestyle and 200m individual medley, which he won in world record time. The 26-year-old also won the 200m backstroke and gave the United States a record fourth straight 4x200m medley world title with a super-fast final leg, after a slow lead-off from Phelps. FINA's doping control review board chairman Andrew Pipe said there were no positive dope tests during the meet, which was hit by controversy when Brazil's Cesar Cielo escaped a ban for testing positive for a banned diuretic