American Kristin Armstrong joined a select club of cyclists when she added the Olympic time trial gold to her 2006 world title here on Wednesday.
Cambridge University graduate Emma Pooley of Britain claimed the silver with triathlon Iron Man specialist Karin Thurig of Switzerland taking a second consecutive Olympic bronze after her third place in Athens.
Armstrong, 35, was nearly four seconds behind early pacesetter Pooley after the diminutive Englishwoman had set a searing pace on the nine kilometre climb leading to the first time check at 10.8 km.
However the American specialist battled a headwind on the ensuing downhill and flat sections to steadily reduce her deficit before coming over the slightly uphill finish line in a winning time of 34min 51sec.
Despite being told she had won, Armstrong - who is no relation to seven-time Tour de France winner Lance - refused to believe she had just achieved her childhood dream.
"The Olympic Games is every four years and this race is one day and you cannot give up until you cross that finish line," said the Tennessee native, who now resides in Idaho. "Someone told me at the top that I had the best time, but I really couldn't celebrate until the last person crossed the finish line!"
Pooley played a pivotal role in teammate Nicole Cooke's triumph on the hilly sections of the women's road race Sunday when the Welshwoman handed Britain their first gold of the Games.
But Pooley, whose engineering degree has now led her to study part-time for a Phd, came into the race with hopes of a medal having previewed the course in December last year when she rode up the climb in freezing snow.
It was then that she realised she would feel more comfortable with a specially adapted set of handlebars that would leave her less aerodynamic, but far more comfortable. "If you're less aerodynamic but more comfortable and you can go faster then it's worth it," said Pooley. "I knew when I came here in December, when it was freezing and snowing, that it was a hard climb."
Pooley's tactics paid dividends and she had the fastest time over the first half of the course. She knew she would need it because the taller specialists would gain time on the remainder of the course. "I knew when I was four seconds down from Emma that I had to turn it on in a big way. I knew they would both be strong on the downhill," added Armstrong.
Pooley's predictions came true, as both Thurig, who was 36secs behind her at the 10.8km mark, and Armstrong gradually began to eat into her lead. "I heard on my radio earpiece that I was behind Emma," said the 36-year-old Swiss, a former two-time world champion. "I knew she was a strong rider but I wasn't too worried. I knew the best part for me was still to come."
Delighted with her second consecutive bronze from the Olympics time trial, Thurig put her performance on the spectacular course which finished at the Great Wall of China into perspective. "This course was uphill so it didn't really suit me," she added. "You have to change a lot of gears and change the rhythm a lot, so it's really demanding. "It's a beautiful course, but I really suffered today so I couldn't really enjoy it."
Results:
Women's Individual Time-Trial
1. Kristin Armstrong (USA) 34:51.72.
(Average speed 40.4 km/h)
2. Emma Pooley (GBR) at 24.29.
3. Karin Thurig (SUI) 59.27.
4. Jeannie Longo-Ciprelli (FRA) 1:00.90.
5. Christine Thorburn (USA) 1:02.44.
6. Judith Arndt (GER) 1:08.05.
7. Christiane Soeder (AUT) 1:29.03.
8. Priska Doppmann (SUI) 1:36.07.
9. Zulfiya Zabirova (KAZ) 1:37.75.
10. Susanne Ljungskog (SWE) 1:41.78.
11. Hanka Kupfernagel (GER) 1:43.33.
12. Tatiana Guderzo (ITA) 1:46.25.
13. Linda Melanie Villumsen Serup (DEN) 1:58.90.
14. Marianne Vos (NED) 2:06.95.
15. Nicole Cooke (GBR) 2:22.53.
16. Natalia Boyarskaya (RUS) 2:22.93.
17. Gao Min (CHN) 2:23.51.
18. Mirjam Melchers-van Poppel (NED) 2:59.87.
19. Marta Vilajosana (ESP) 3:03.27.
20. Maryline Salvetat (FRA) 3:18.00.
21. Emma Johansson (SWE) 3:37.11.
22. Oenone Wood (AUS) 4:01.73.
23. Edita Pucinskaite (LTU) 4:03.65.
24. Alexandra Wrubleski (CAN) 4:23.70.
25. Meng Lang (CHN) 5:59.89.