Cyclist Mark Colbourne has secured Britain's third gold medal of the Paralympics - but there was controversy when his teammate Jody Cundy was disqualified at the velodrome.
Colbourne, 42, clocked a world record time to triumph in the C1 3km individual pursuit, ahead of China's Li Zhang Yu.
The win marked a fantastic start to the Games for the Welshman - who bagged a silver in the C1-2-3 1km time trial on day one.
He dedicated his gold to his late father, his mother who was in the crowd and his daughter.
But moments before Colbourne's victory, there were extraordinary scenes at the cycling as reigning champion Jody Cundy was disqualified after a faulty start in the C4/C5 1km time trial.
The British rider's wheel appeared to spin in the start gate and he stopped cycling, expecting an automatic restart.
But officials ruled the problem was down to rider error rather than an equipment fault and boos rang out around the arena as it became clear that Cundy would not get another chance to defend his title.
A clearly distraught Cundy - who was awarded an MBE in 2009 for his athletic achievements - had to be restrained by teammates as he left the track after aiming a volley of expletives at race commissaires and throwing a water bottle to the ground in disgust.
Sky's Orla Chennaoui, who was at the Velodrome, tweeted: "Cundy screaming at his coach... 'Do you know what it's like to dedicate four years of your life for 1 minute and not get the chance to race?"
Cundy's coach Chris Furber said they had appealed in vain to the sport’s governing body, the Union Cycliste Internationale (UCI).
Furber said: "During the countdown I felt the gate didn't release right.
"We spoke to the UCI, we asked them to review the TV footage, they ruled the TV evidence would be inadmissible.
"I tried to argue with them. I told Jody and naturally Jody's reaction was as you saw."
Amid the drama, Britain's world champion Jon-Allan Butterworth, who lost his left arm in a blast while serving with the RAF in Iraq in 2007, picked up silver in the event behind Spain's Alfonso Cabello, who broke the world record on his way to gold.
The 26-year-old from Sutton Coldfield made his journey to the Games via the battlefield and Help for Heroes' Battle Back scheme.
Inspired by watching athletes like Sir Chris Hoy in the 2008 Olympics, he went to a selection weekend in Newport and was accepted on to the British Paracycling Programme in January 2009.
Aileen McGlynn and Helen Scott won Britain's first medal on day two, clinching silver behind Australia in the blind and visually impaired tandem 1km time trial at the Velodrome.
"I'm a little bit disappointed but at the same time I'm really pleased to win a silver," said McGlynn. "I'd like to thank the crowd for coming along and supporting us all so much."
Aled Davies secured Great Britain's first athletics medal with bronze in the F42/44 shot put with a throw of 13.78m.
The team is following the success on Day One , when cyclist Sarah Storey and swimmer Jonathan Fox both bagged gold medals, and three silver and two bronze medals were also won for Britain.
:: Click here to see the medals table
Ex-soldier Derek Derenalagi, who lost his legs in Taliban blash in Afghanistan in 2007, is also sure to draw a crowd as he goes for gold in the F57 discus.
Derenalagi, who was born in Fiji but now lives in Hertfordshire, had his legs blown off in a Taliban blast in Afghanistan in July 2007.
UK Sport has set ParalympicsGB the minimum target of winning 103 medals from at least 12 different sports, with the overall goal of once again finishing second in the medal table.
Britain finished second for the third time in a row in Beijing after bagging 102 medals, including 42 golds.
One of the biggest hopes for gold, swimmer Ellie Simmonds, will compete at the weekend - but her race has been hit by controversy after a row over reclassification.
World record holder and American paralympic swimmer Victoria Arlen was declassified on Monday after the International Paralympic Committee (IPC) ruled she was not disabled enough.
But the 17-year-old was reinstated on Thursday after an appeal by the US team was upheld. A final decision will now be made by the IPC after she has competed.