Hosts South Korea were the Asian Games' surprise first-day medal leaders on Saturday but they had to share the limelight with China and record-breaking North Korea. South Korea won titles in cycling, fencing, equestrian and wushu to narrowly top the medals table ahead of China as the Olympic-size event rolled into action in Incheon. They got off to a rocky start when China, led by the unheralded Zhang Menyuang, beat them to the Games' first gold in the women's 10 metre air pistol.

North Korean pocket rocket Om Yun Chol broke his own weightlifting world record at the Asian Games. Less than 24 hours after a vibrant opening ceremony marked the launch of the 17th Asiad, Om hoisted more than three times his own bodyweight with a superhuman lift of 170kg in the clean and jerk.

Standing just 1.52m tall (5ft) and weighing 56kg (123lbs), Om's mighty lift came near the end of a day in which 18 gold medals were split between eight countries. China's Zhang Mengyuan won two gold medals, in the women's 10 meters air pistol event and in the team event. Some 9,500 athletes from 45 countries are competing at the Games, the world's second-biggest multi-sport event after the summer Olympics, with 439 gold medals in 36 sports up for grabs. And while there are 14 more days of competition to go, it is hard to imagine a gold medal being celebrated with such joyous abandon as Om displayed at the Moonlight Festival garden venue.

The London Olympic champion let out a roar of triumph, raced to celebrate with his coach, did a lap of honour draped in the North Korean flag, then posed on the podium with a razor-sharp salute as the national anthem played in his honour. The scene would not have pleased the conservative groups who had demanded Incheon organizers take down North Korean flags flying around the city in the lead-up to the Games, but the crowd's reaction to Om's win was one of delight, not distrust.

Tensions between North and South Korea are high and the two states are still technically at war after the 1950-53 Korean War ended in a truce, not a peace treaty. "I am very happy," the 22-year-old Om told reporters. "Whenever our people face difficulty, we come together and make it through the rough time."

South Korean fans also had good reason to cheer their own athletes as they took five gold medals -- in wushu, fencing, cycling and equestrian. Lee Ha-sung picked up the hosts' first gold in the men's wushu changquan and his coach, Park Chan-dae, said Lee had accomplished something he never could. "He has achieved my dream for me," said Park. "Although I won gold six times in the Wushu World Championships, I only got a silver medal at the Asian Games."

Lee's combination of whirling kicks, athletic leaps and intricate hand movements earned him a score of 9.71 points to take gold in the martial arts discipline, ahead of Macau's Jia Rui (9.69) and Japan's Daisuke Ichikizaki (9.67).

But victory in the men's team sprint and men's epee late in the day took South Korea to five golds. China, who won a record 199 gold medals at the 2010 Games, led the table for most of the day before being caught by South Korea. Army sharpshooter Jitu Rai held his nerve on the final shot to snatch 50m pistol gold from Vietnam's Nguyen Hoang Phuong and put India amongst the golds. And China's Zhong Tianshi rode to victory in the women's team sprint, a day before she challenges Hong Kong's Olympic medal-winner Sarah Lee Wai-sze in the keirin.

Through hosting Asiad, Incheon has become South Korea's most indebted city and Vietnam pulled out of organising the next Asian Games because of the cost involved. China's Zhang is only ranked 29th in the world but after helping win the team 10m air pistol title, she beat South Korea's hot favourite Jung Jee-Hae into second place. Chinese coach Wang Yifu said her triumph was doubly impressive as organisers had "deliberately" arranged the 10m air pistol as the first event, hoping for a home victory. "It was hard for us to win this medal," Wang said.

Thailand's equestrian princess Sirivannavari Nariratana was down the field in the dressage, but there was an emotional team win for South Korea's Kim Hyun-Sub, whose uncle was crushed to death by his falling horse at the 2006 Asiad.

On day two, Chinese swimming superstar Sun Yang will meet South Korea's Park Tae-Hwan in the first of three explosive races in the pool. And China will want to find an immediate response after coming off second best to South Korea on the first day of full competition. "We have been leading both medal and gold medal tables at nine straight Asian Games," said China's delegation chief Liu Peng. "We certainly want to keep winning this time."