1) JEREMY WARINER V LASHAWN MERRITT, 400 METRES
Olympic and world champion Wariner has dominated the 400 metres since before the 2004 Games. Compatriot Merritt has been in his slipstream throughout and is getting closer. Wariner, who in Athens became the first white man to win a sprint gold since the boycotted 1980 Games, remains favourite to retain his title but things have certainly got closer since Merritt bet him twice earlier in the season. The second of those victories came in the U.S. trials when he said afterwards: "Once I got into the home stretch I was smelling Beijing and victory." Only Michael Johnson, something of a mentor for Wariner, and Butch Reynolds have run faster than Wariner's best time of 43.45.
2) KENENISA BEKELE v HAILE GEBRSELASSIE, 10,000 METRES
The winners of the last three Olympic 10,000 metres titles go head-to-head with Ethiopia's Gebrselassie hoping to roll back the years for a sign-off triumph over his compatriot. Gebrselassie won gold in 2000 and 2004, both times beating Kenyan Paul Tergat in terrific races. As world record holder and four-times world champion he was the undisputed 10,000 king before moving on to the marathon.
Bekele took the older man's world records at 5,000 and 10,000 metres, succeeding him as Olympic champion and notching up three world titles. Gebrselassie, now 35, nine years older than Bekele, opted out of the Beijing marathon because of concerns over the air quality.
3) MICHAEL PHELPS v MARK SPITZ, SWIMMING
Phelps, born after his fellow American retired, is engaged in a battle with Spitz for the title of the greatest swimmer of all time. Spitz has held that mantle since he won seven gold medals, all in world record time, at the 1972 Munich Olympics. Phelps came close to matching his mark at Athens four years ago when he collected six golds but is chasing eight in Beijing. Phelps is due to swim the 200 and 400 metres individual medley, the 100 and 200 butterfly, the 200 freestyle and three relays in Beijing -- and is favourite to win all of them. Australian head coach Alan Thompson says the American is more than capable of the record feat but his team mates Ian Crocker and Ryan Lochte could spoil the party.
4) KATIE HOFF v STEPHANIE RICE
American Katie Hoff and Australia's Stephanie Rice will clash in women's individual medleys. Hoff won both events at last year's world championships before teenager Rice threw down the challenge when she broke the world records for both events at this year's Australian Olympic trials. Hoff regained her record in the 400 during the U.S. trials. Rice was romantically linked with Eamon Sullivan but they called off their relationship just before the Beijing Games. Sullivan broke Alexander Popov's world record for 50 metres this year but lost it to Bernard a few months later before regaining it at the Australian trials.
5) ISABELL WERTH V ANKY VAN GRUNSVEN, EQUESTRIANISM
Dutchwoman Van Grunsven has stopped giving interviews so she can throw everything into beating her equestrian dressage rival of the past two decades, Germany's Werth, and winning her third successive Olympic gold. She clinched her ninth World Cup title this year by beating Werth, who won silver in Barcelona and then captured the gold medal at the 1996 Atlanta Games by edging out the Dutchwoman. Werth also won silver in 2000. Beijing is almost certainly the sixth and last Olympics for van Grunsven because her children are more important to her than a gold nowadays.
6) YANG WEI V THE HORIZONTAL BAR, GYMNASTICS
With no Paul Hamm in the field, the only obstacle standing in Yang's way to winning the Olympic all-round title is likely to be the horizontal bar. Four years ago the Chinese favourite was leading the competition going into the final rotation but his Olympic dreams came crashing down when he lost his grip on the bar and finished out of the medals. At the 2007 world championships, Yang again failed to master his hold on the apparatus and suffered a crashed landing. This time, such was the lead he had built up over his rivals, the fall could not deny him a place on the top of the podium.
7) CHINA V US WOMEN'S TEAMS, GYMNASTICS
China reigned supreme at the 2006 world championships before being dethroned 12 months later by the United States, who won their first world team title on foreign soil in Stuttgart. The Americans will be relying on the dynamic skills of Shawn Johnson and the artistry of Nastia Liukin while the Chinese have a team packed with specialists led by vault and floor supremo Cheng Fei, fourth in the 2004 Olympics in the floor. Carly Patterson of the U.S. won the individual all-round in Athens in 2004 and the American team were second behind Romania in the team competition.
8) TONY ESTANGUET V MICHAL MARTIKAN, CANOEING
France's Estanguet is seeking a third successive gold in the C-1 and faces a serious threat from Slovak Michal Martikan, the 1996 champion. In 2004, Martikan was already celebrating the gold when a review showed he had hit a gate on the course. He took silver because of two penalties. Estanguet reckons the brutal conditions on the Beijing course could be decisive: "The force of the water means you have to fight."
9) CHINA V REST OF WORLD, TABLE TENNIS
Will anyone stop the host country from sweeping all four table tennis golds? The odds are stacked against the world -- China has taken 16 of the 20 golds since the sport debuted at the Olympics. The host country is most vulnerable -- in relative terms, at least -- in the men's singles competition. South Korean Ryu Seung-min won in Athens in 2004. Germany's Timo Boll or Belarusian Vladimir Samsonov could play spoilers in Beijing. However, the top four in the men's rankings and the top five in the women's are Chinese.
10) MAHE DRYSDALE V OLAF TUFTE, ROWING
Tufte of Norway, who took silver in doubles sculls in 200, won the 2004 single sculls gold medal and it was after those Games that Drysdale decided to try his luck at the event. Drysdale has won the last three world championships and had to fight off a challenge from Rob Waddell, who won gold in 2000, for the New Zealand Olympic spot after his compatriot came back from a seven-year retirement. Drysdale said that challenge affected his preparations for Beijing.