(Updates with swimming wins, adds details)
* Swimming surprises cap dramatic day at Games
* French, Lithuanian victories against the odds
* Questions over Chinese swimmer's stellar times
* Swiss soccer player expelled for racist tweet
LONDON, July 30 (Reuters) - Lithuanian swimmer Ruta
Meilutyte struck Olympic gold on Monday in the women's 100
metres breaststroke aged just 15, capping a dramatic day in the
pool where Frenchman Yannick Agnel also beat an American
favourite to win the men's 200 metre freestyle.
On the third full day of competition in London, Swiss soccer
player Michel Morganella was expelled for an abusive message on
Twitter after his team's defeat by South Korea.
And Chinese swimming sensation Ye Shiwen's world record win
in the 400 individual medley on Saturday raised eyebrows in the
world's media about the 16-year-old, prompting her to deny that
she had taken performance-enahncing drugs.
But it was heroics in the water that set ablaze the Olympic
village, and in particular those of Meilutyte, the first swimmer
from her country to win an Olympic medal.
The Lithuanian had to do it the hard way, surviving a fierce
challenge from American Rebecca Soni, the reigning world
champion in the event, and just holding her off at the death.
"I can't believe it," a stunned Meilutyte managed to say in
a post-race poolside interview.
Agnel, a 20-year-old who reads the poetry of Charles
Baudelaire between races to relax, captured a second gold medal
in 24 hours after his stunning anchor leg won France the 4x100
freestyle relay the previous night.
And he had to beat a stellar field including U.S. world
champion Ryan Lochte who ended up fourth.
The United States caught up some ground on China in the
medals rankings, however, with two late golds in the pool.
Matt Grevers collected his first individual gold in the
final of the men's 100 metres backstroke while teenager Missy
Franklin won the women's 100 backstroke.
It took the U.S. gold tally to five by the end of the third
full day of competition, still four golds behind medal table
leaders China on nine.
American Michael Phelps has a chance to make history on
Tuesday by becoming the most decorated Olympian if he scores
medals in two men's finals.
It would take his tally to 19, one more than the current
all-time record of 18 held by Soviet gymnast Larisa Latynina.
DOPING QUESTIONS
At a press briefing at the main Olympic site in London's
East End, reporters asked Arne Ljungqvist, International Olympic
Committee medical chief, whether Chinese Ye's sensational
victory was in any way suspicious.
"I say no," replied Ljungqvist, who has 40 years experience
in anti-doping. "Should a sudden raise in performance or a win
be primarily suspect of being a cheat then sport is in danger
because this ruins the charm of sport," he added.
Ye, who turned 16 in March, powered to gold in the 400
metres individual medley at the weekend and became the first
female swimmer to break a world record since the ban of
high-tech suits, taking over a second off the previous
benchmark.
She brushed aside doping suspicions, saying Chinese athletes
were clean.
"My results come from hard work and training and I would
never used any banned drugs. The Chinese people have clean
hands," she told reporters.
SWISS EXPELLED
At the first Games where social media has become such a
major issue, Switzerland's Morganella was expelled for an
offensive tweet.
It follows the withdrawal last week, before the July 27-Aug.
12 tournament got under way, of Greek triple jumper Paraskevi
Papachristou for another tweet deemed racist.
A row over empty seats at venues across London rumbled on,
with Olympic organisers under pressure to fill arenas and
placate a public furious at seeing TV pictures of unused places,
having been told months ago that venues had sold out.
British Prime Minister David Cameron said volunteers,
soldiers and the public would be able to take some of the
available places, but added: "You'll never have complete
eradication of empty seats."
Ticketing confusion also led to the opposite problem -
overcrowding - in at least one instance on Monday.
Dozens of angry ticketholders trying to get into the men's
10m air rifle competition at Royal Artillery Barracks were
turned away because the venue was too full.
But London's transport system largely defied predictions of
gridlock on the first regular working day of the 2012 Games.
Transport bosses expect an extra three million journeys per
day on top of the usual 12 million during the Games, an Olympian
test for an underground train network that first opened in 1863
during the reign of Queen Victoria.
On the first morning rush hour since the Games opened on
Friday night, commuters said buses, trains and the metro were
working surprisingly smoothly with a few hiccups, and roads were
generally clear.
Chris Round, 23, from Boston, Massachusetts, took the
Underground and Docklands Light Railway to watch the judo.
"It was real easy to get to," he said. We just got on the
first train that came. It was kinda crowded but it wasn't bad."
HOST HOPES
Host nation Britain was still waiting for its first gold
medal, but a bronze in the men's team gymnastics felt almost as
good as it ended a 100-year wait for any medal in the event.
Princes William and Harry, grandsons of Queen Elizabeth, led
the support at a raucous North Greenwich Arena, and the loud
cheers were muted only slightly when an initial silver medal was
downgraded following an appeal by the Japanese team. Other
royals were also at the event.
In other medal action, China's Cao Yuan and Zhang Yanquan
won the men's synchronised 10 metre platform diving and
compatriot Li Xueying broke two Olympic records on the way to
the women's 58 kilogram weight division in the weighlifting.
Romania took its first gold with Alin George Moldoveanu's
surprise victory in the 10m air rifle event, and on a packed day
of sport Russia's Mansur Isaev triumphed in the 73kg men's judo
after a fast and furious fight with Japan's Riki Nakaya.
(Additional reporting by Karolos Grohmann, Michael Holden,
editing by Peter Millership)