It's gold number 21 from Laura Trott with cycling victory
Laura Trott has won gold in the women's omnium after a breathtaking final in the Olympic velodrome.
The 20-year-old cyclist claimed her second gold of London 2012 when she recorded the fastest time in the 500m time trial, the final of six events.
Trott's victory was equally unlikely. The Briton, racing in her first Olympics, trailed Hammer by two points going into the trial, and needed to beat the American by three clear places.
it seemed an unlikely feat, but the British cyclist - already the proud owner of a gold medal in the team sprint - stormed off the blocks with incredible pace and held her lead over Hammer finishing well ahead of Hammer.
After discovering she'd done enough to win gold, the tearful Trott pedalled over to screaming family, friends and teammates in the front row of the velodrome.
She told the BBC: 'I can't believe this has happened to me.
'I came into today not feeling as good as yesterday and to finish off with that last 500m is unbelievable.
'I'm peaking at the right time and it's all thanks to the coaches really and the support of the crowd. I'm so happy I can't thank people enough really.'