BEIJING, Aug. 17 (Xinhua) -- Oussama Mellouli showed no sign of slowdown in the final meters of the men's 1,500-meter freestyle final here on Sunday to grab the second ever Olympic gold for Tunisia, dashing Australian giant Grant Hacett's dream of third consecutive Olympic title in the event.

　　Mellouli kept himself in the fifth or sixth place out of eight finalists in the first 14 laps, then began to surpass the big fish ahead of him one by one in a modest way.

　　The 24-year-old swimmer grabbed the leading position after the 1,050-meter mark and never conceded it until touching the wall first in 14 minutes and 40.84 seconds.

　　"I've been waiting for this moment for two years. I had expectations for the 400-meter freestyle but this a great surprise, " said Mellouli. "I felt good in the first 400 meters. At 800 and 900 meters I started believing I could win."

　　After trailing Canadian Ryan Cochrane in the first three laps, the 28-year-old Hackett pushed himself forward a little. But after the 550-meter mark, the two time Olympic champion in the grueling event was either behind Cochrane or Mellouli, having to settle for a silver medal in 14:41.53.

　　Cochrane took the bronze in 14:42.69 while Chinese pair Zhang Lin and teenager Sun Yang ranked seventh and eighth.

　　Hackett has remained a benchmark swimmer in the men's 1,500-meter freestyle since 2001, when he clocked 14:34.56 in the world championships in Fukuoka, Japan. The mark remained intact over the past seven years.

　　"It's disappointing, yet so close. To get second is great, but three in a row would have been nice," said Hackett.

　　Hackett squatted for a while after pulling himself out of the pool, exhausted and disappointed to know his dream of becoming the first male swimmer in Olympic history to clinch three titles in a row in the same event was shattered to pieces.

　　"I gave it everything today, it was a hard race. I gave it everything I could," said the big fish, who only managed a sixth place in the men's 400-meter freestyle last Sunday, while South Korean prodigy Park Tae-hwan and Chinese hopeful Zhang Lin made one-two finish.

　　The Australian team captain also brought home a bronze from the 4x200-meter freestyle relay on Wednesday.

　　Mellouli first established his fame at last year's World Championships, where he won the silver in the 400-meter freestyle and became the first swimming world champion from Tunisia by winning the 800-meter freestyle.

　　However, Mellouli was soon discovered to have tested positive for the banned substance amphetamine, allegedly taken to help concentrate for intensive college study sessions and not for any competitive advantage in swimming.

　　Due to a 18-month retroactive competition ban imposed on him September 11, 2007 by the Court of Arbitration for Sport and retroactive to November 30, 2006 - for doping, all of these 2007 achievements have been voided.

　　"It's just been a hard, painful, long, training period to me," said Mellouli. "I just kept my head down, did my wightlifting, did my running,did my stretching...I gave it all I got, that's what I did. Grant (Hackett) made a perfect comeback in the last 100 meters and thank god I had a little juice left to finish it."

　　Before Mellouli's sensational win, Tunisia's only Olympic gold medal was credited to distance runner Mohamed Gammoudi, who claimed victory in the 5,000-meter event at the 1968 Games.