Lizzie Armitstead won Britain's first medal of the 2012 Olympics as Marianne Vos claimed gold for the Netherlands in the women's road race on Day Two.Armitstead took the silver with Russian Olga Zabelinskaya third in a thrilling rain-soaked 140km race that ended on The Mall in front of Buckingham Palace.Zabelinskaya instigated a breakaway with 25km to go and Armitstead and pre-race favourite Vos went with her.Armitstead attacked Vos on The Mall but the Dutch rider had too much power. "I'm so glad I committed to that break," said the 23-year-old from Otley in Yorkshire. "I was umming and aahing but I'm really happy I went with it. I should've jumped earlier in the sprint, but never mind."Vos was always the one to watch so I was following her around. We both got in an early break, but I thought it was too early so I waited."On the support she received from British fans lining the road, Armitstead added: "It is the most special thing I've ever experienced in my life. It's so crazy and so inspiring. It was absolutely amazing. I didn't even feel my legs, it was just so special."Just like the men's race on Saturday, which ended in such disappointment for Team GB, the key break came on the final lap of the Box Hill circuit.The first hour of the race had been a relatively sedate ride out through south west London towards the Surrey hills.But the next two hours saw attack after attack, as riders from all the leading nations tried to break the race apart.The Dutch were particularly prominent in this phase, although Britain's Emma Pooley, the time-trial silver medallist at the 2008 Beijing Olympics, was also in the thick of the action.But just when matters seemed to be calming down for the long, fast drag back to London, the unfancied Zabelinskaya broke clear.Armitstead, Vos and the American Shelley Olds realised that this was a make-or-break moment and tore off in pursuit.Within a matter of minutes, the three chasers had caught the 32-year-old Russian and a tacit agreement was reached: if we work together we have a three-in-four chance of a medal.In team time-trial mode, the four riders pulled out a lead, 12 seconds, then 18, before stabilising at 25 as the peloton struggled to organise a chase. And then disaster struck for Olds, the American punctured and suddenly those three-in-four odds got even better.At one point, it seemed as if Zabelinskaya was hanging on too, but as the miles clicked down back to The Mall, she dug deep to do her bit for the Anglo-Dutch-Russian joint venture.This, of course, was the perfect scenario for the sprinters Armitstead and Vos.Armitstead has a great turn of pace, honed during her formative years on the track, but she was no match for the peerless Vos, so often a bridesmaid in the big competitions but too good on Sunday.Nicole Cooke, who won this race four years ago, finished 31st, with Pooley, who suffered a mechanical problem towards the end of the race, 40th, the last of the riders to complete the course.