The Olympics got its first security scare — a false alarm — with Britain's Ministry of Defence scrambling a Typhoon fighter jet to intercept a commercial airliner too close to the London Olympics site.
The Games also got their first diplomatic incident when North Korea's women's soccer team refused to take the field for nearly an hour for its match against Colombia after organizers mistakenly displayed the South Korean flag on a giant screen at Hampden Park stadium during player introductions.
Organizers quickly acknowledged their mistake and said "steps will be taken to ensure this does not happen again."
Stephanie Houghton gave Team GB its first win of the games by firing home a second-half free kick to seal a 1-0 football win over New Zealand at the Millennium Stadium in Cardiff.
The match was one of six women's soccer games that opened the sport program for the London Games.
The International Amateur Athletics Federation announced it had suspended eight athletes for two years and one for four years for "sophisticated doping," including one case of human growth hormone and two of synthetic testosterone.
Three were caught in retests of samples from last year's world championships in Daegu, South Korea, and six were caught in biological passport tests, which measure changes in an athlete's blood profile.
"This is the second finding of growth hormone in athletics and one of only a very few to date in sport as a whole," the IAAF said.
It will probably not be the last. A new doping test for human growth hormone will be used at the London Olympics after it was cleared just weeks ago following a 13-year process.
David Howman, director general of the World Anti-Doping Agency, said the new procedure will be used alongside the existing test for HGH.
Among those suspended was Ukraine's Nataliya Tobias, who won a bronze medal in the 1,500 metres at the 2008 Beijing Olympics. She tested positive for testosterone in further analysis of urine samples from Daegu, where she finished ninth in the 1,500.
The IAAF said Bulgarian sprinter Inna Eftimova, who was eliminated in the 100-metre heats in Daegu, tested positive for synthetic growth hormone.
Also out of the games was Greek triple jumper Voula Papachristou, kicked off her country's team for a tweet mocking African immigrants.
Commenting on the widely reported appearance of Nile-virus-carrying mosquitoes in Athens, Papachristou wrote: "With so many Africans in Greece, the West Nile mosquitoes will be getting home food!!!"
The Hellenic Olympic Committee ejected Papachristou "for statements contrary to the values and ideas of the Olympic movement."
The 23-year-old later apologized — also via social media — saying "I could never believe in discrimination between human beings and races."
London's Olympic transport plan got a major test, as lanes reserved for Olympic VIPs came into force and the city's creaky subway system struggled with glitches.
Traffic jams blocked some of the main routes into the city as the wildly unpopular "Games Lanes" came into force. The 48 kilometres of lanes are to operate from 6 a.m. to midnight throughout the games, and cars or taxi cabs that stray into them face a 130-pound ($200) fine.
Thousands of London drivers have switched to public transport, only to encounter severe delays on several underground subway lines caused by power supply problems and signal failures. Long holdups were reported Wednesday on the city's Central and Hammersmith subway lines with ripple delays affecting other lines.
Even London's new river-crossing cable car — opened just last month — hit a problem, with a technical fault stranding passengers above the River Thames for roughly half an hour.
Officials who have been telling Londoners for weeks to allow extra time for travel or just stay home advised that most British of reactions: a stiff upper lip.
"There will be a lot of disruption and London is a congested city anyway," Transport Secretary Justine Greening told BBC television.
It wasn't all bad traffic news. Fans flying into London's Heathrow Airport could breathe a sigh of relief after immigration staff called off a pre-Olympics strike. The 24-hour-long walkout had been planned for Thursday, potentially snarling incoming traffic on one of the busiest days at Europe's busiest airport.
One airliner caused the Games' first security scare when it flew a bit too close to the Olympics for comfort.
A Typhoon fighter was scrambled shortly before noon because the plane was not in contact with air-traffic control.
Communications were quickly restored and no further action was required, the ministry said.