LONDON (Reuters) - Lithuanian teenager Ruta Meilutyte survived the ultimate test of nerves to win the women's 100 meters breaststroke gold medal at the London Olympics on Monday.

The 15-year-old not only became the first swimmer from her country to win an Olympic medal she did it in under extraordinary circumstances.

The start, a time when swimmers are already battling their nerves, was delayed by a technical malfunction that saw the starter's gun go off before he had called "on your marks". American Breeja Larson dived into the pool on the gun but was able to race because of the malfunction.

The eight finalists sat down while the problem was fixed and an unfazed Meilutyte still got off the blocks fastest and led at the turn but then had to survive a fierce challenge from American Rebecca Soni, the reigning world champion in the event.

The more experienced Soni drew level in the final few strokes but Meilutyte kept her cool and got her hands on the wall first in one minute, 05.47 seconds.

Soni was second in 1:05.55 while Japan's Satomi Suzuki finished third in 1:06.46.

Australia's Leisel Jones, the defending Olympic champion who won a silver medal at the 2000 Sydney Games when she was 15, finished fifth overall in her fourth and final appearance at the Games.

(Reporting by Julian Linden; Editing by Greg Stutchbury)