Liu Xiang powers to stunning 12.87sec (2.4m/s) 110m Hurdles victory in Eugene (Kirby Lee - Image of Sport) © Copyright

Pre-Olympic showdowns galore on tap in London – PREVIEW – Samsung Diamond League

London, UKSome 16 Olympic and 15 World champions are set to make an early appearance in the Olympic host city this weekend as the sporting focus switches momentarily from the east of the British capital to its southern edge where the latest stage of the 2012 Samsung Diamond League sets down for the Aviva London Grand Prix at Crystal Palace.

Not surprisingly, with two weeks to go to the London 2012 Opening Ceremony, the organisers (UK Athletics) have packed the fields with British Olympic hopefuls – around 50 in all – including the country’s only defending champion Christine Ohuruogu and its two current World champions Dai Greene and Mo Farah.

Hurdles showdown in the spotlight on day one - Friday (13)

But with a two-day programme to fill, there’s plenty of global stars on show too, not least Liu Xiang whose tussle with world leader Aries Merritt and World champion Jason Richardson at 110m Hurdles will be one of the highlights on Friday evening.

Liu Xiang’s return to the Olympic arena in three weeks’ time, four years after he brought anguish to the Chinese nation by not completing his heat in Beijing, could be one of the stories of the London Games. Friday’s race will give us a good idea of whether the face of Beijing, the Athens gold medallist, is in shape to regain his Olympic title in London.

Liu Xiang currently sits second in the world rankings, just 0.04s behind Merritt with Richardson the only other man under 13 this year. They’ll be joined by the fourth quickest in the world, and USA’s third Olympian, Jeff Porter whose wife Tiffany runs the women’s sprint hurdles on Saturday. Decathlon World record holder Ashton Eaton is also in the field.

Liu Xiang’s last race was in Eugene at the beginning of June and he admitted he needs races, especially after seeing Merritt and Richardson in such form.

"I came here to get some competition," he said. "I’ve been training hard but training is different to competition.

"I wasn’t surprised at all [by his rivals’ times at the US Trials] because they are very, very good hurdlers. I will need to focus to get a good result. The 110m hurdles is an event where you can’t make a mistake."

Gay vs Powell, the next round

Like Liu, Tyson Gay and Asafa Powell also have something to prove on the Olympic stage. The second and third quickest in history, they found themselves the forgotten men of world sprinting last year, both missing the World championships as Yohan Blake rose to become chief challenger to Usain Bolt.

Gay’s battling win against Justin Gatlin in Paris last Friday could set him up for a repeat of his victory here two years ago when he defied torrential rain and a headwind to clock 9.78. Given the state of Britain’s sodden summer so far, he may well have to cope with the same conditions again.

"I always get a good reception here and wouldn’t pass the opportunity to race here and sample the weather," he said.

Powell, meanwhile, will be hoping his vulnerable groin holds up to the strain, while the likes of Michael Frater, Nester Carter, Kim Collins, Keston Bledman, Ryan Bailey and a host of Britons, led by Dwain Chambers, try to get among the big two.

Greene-Culson rivalry continues

Greene will again test himself against Javier Culson, just a week after he chased the Puerto Rican to the line in Paris, the pair recording the two quickest times in the world this year. World numbers three, four and six – Bershawn Jackson, Michael Tinsley and Felix Sanchez – are also in the line-up as is Greene’s near-namesake and fellow Briton, Jack Green.

After a troubled start to the year, Greene admitted he was surprised to run so quickly in Paris when he almost caught the fast-starting Culson with a strong finish. "I knew I was in good shape but I didn’t know I’d go quite that fast yet," he said. "It’s been a tough few months to get hereto this point but if I have another good run here my confidence will be sky high.

"I think Culson’s probably the best in the world at the first five hurdles, and I’m probably the best at the last five, which makes for a great race when we’re both in form."

Cheruiyot’s final prep for Olympic double

Vivian Cheruiyot will be looking to continue her unbeaten season in the women’s 5000m, and extend her winning streak at the distance which now stands at 10 races over nearly two years.

"I don’t expect to run a great time here," she said. "I’m just here to see how my body feels and get ready for the Olympic Games. Tomorrow is only about winning then I go back to Kenya."

The double World champion will have plenty of company from fellow Kenyans Sylvia Kibet, Linet Masai and Veronica Nyaruai, while Genet Ayalew provides the threat from Ethiopia.

All eyes on Farah

All eyes will be on Farah in the men’s 5000m where the world champion expects to win against Commonwealth champion Moses Kipsiro and a clutch of Kenyans, even if he’s not expecting the race to be as quick as the Ethiopian-led 5000m blast in Paris when six men ran faster than his personal best.

Not that Farah is letting that worry him. "I think it was one of those races," he said. "I think if those guys can run that time I should be able to go a lot faster too.

"These are the guys I compete against week in, week out. Obviously, the Olympics are going to be a lot more tactical."

The women’s 400m hurdles features Russia’s European champion and world number two Irina Davydova against Jamaican trio Melaine Walker, Kaliese Spencer and Nickiesha Wilson, plus T’erea Brown and Tiffany Williams from USA, and British pair Perri Shakes Drayton and Eilidh Child.

Jamaicans and US athletes figure strongly in the women’s 200m too. Kimberlyn Duncan is quickest in the field this year, with Sherone Simpson not far behind.

Another Simpson goes in the women’s 1500m – World champion Jennifer. She races fellow Americans Morgan Uceny and Shannon Rowbury, plus Maryam Jamal and Britain’s two world silver medallists from Daegu 2011 and Berlin 2009 respectively, Hannah England and Lisa Dobriskey.

Lavillenie riding strong momentum

The men’s Pole Vault could be the pick of Friday night’s field events with world leader Renaud Lavillenie in a rematch with Björn Otto, the German who pushed him to 5.97 at the European championships in Helsinki, plus another German Malte Mohr and Australia’s struggling Olympic champion, Steve Hooker.

There’s another Olympic champion in the men’s long jump. Irving Saladino makes his first appearance since crashing out in the Daegu qualifiers last summer. Germany’s European champion Sebastian Beyer and Britain’s world leader Greg Rutherford will be the men to beat, though Rutherford is a man currently trying to refind his early season form.

Lowe vs Chicherova

The discus line-up is another that reads like a who’s who of the world rankings – Virgilijus Alekna, Lawrence Okoye, Zotlan Kovago, Gerd Kanter and Benn Harradine are those from the top 10 – while the women’s High Jump pitches world number one Anna Chicherova against number two Chaunte Lowe with Svetlana Shkolina, Ruth Beitia and Tia Hellebaut also in the mix.

Jeter vs Fraser-Pryce showdown tops day two – Saturday (14)

It will be the women sprinters and hurdlers who come to the fore when the action resumes on Saturday with Shelly-Ann Fraser-Pryce’s head-to-head against Carmelita Jeter perhaps the pick of the day.

The Olympic 100m champion makes her first outing since she knocked Jeter off the top of the world leader board with a scintillating 10.70 area record at the Jamaican championships two weeks ago while Jeter comes fresh from bagging two Olympic berths at the US trials.

Pearson wearing the target

Sally Pearson is another woman in hot form, with four of the world’s five fastest times, and the Australian world champion will be looking to lower her 12.40 world lead from Paris when she faces Danielle Carruthers, the woman she beat in Daegu last summer.

The line-up also includes Brigitte Foster-Hylton and Kellie Wells, ranked number two and three this year, Porter, the British record holder, and Priscila Lopes-Schliep, who will be looking for some compensation after failing to make Canada’s Olympic team.

In the men’s events, the focus shifts to the one-lap race where world champion Kirani James takes on two athletes who have run faster this year – Tony McQuay, 44.49 at the US trials, and Kevin Borlée, who broke the Belgian record running 44.56 at his national championships.

James, who clocked 44.72 back in May, will also face Britain’s number one Martyn Rooney and Chris Brown of the Bahamas.

Montsho the favourite, but Ohuruogo rounding into form

Amantle Montsho will be hoping for another sub-50 time in the women’s 400m. The world champion followed up her 49.54 victory in the African championships with 49.77 in Paris.

Ohuruogu was fourth at the Saint Denis meeting in 50.59, her best of the year, and the Olympic champion is quietly confident that her typically low key build-up to London will again see her peak at just the right time.

After losing to Gay and Gatlin over 100m on home soil last week, Christophe Lemaitre will have his hands full here too, this time over 200m where sub-20 second men Churandy Martina and Nickel Ashmeade provide stiff opposition.

Lagat looking to regain Emsley Carr Mile bragging rights

Bernard Lagat is seeking revenge over Leo Manzano in the men’s mile – the 59th Emsley Carr Mile – following defeat at his compatriot’s hands last year.

The two Americans will have it tough, though, against a field that includes Silas Kiplagat, the world’s quickest 1500m man, and Augustine Choge, world number one over 3000m. Asbel Kiprop’s world lead from Bislett stands at 3:49.22.

With no David Rudisha, Abubaker Kaki will hope to make his mark in the men’s 800m against two confident Britons, Andrew Osagie and Michael Rimmer, plus Polish pair Adam Kszczot and Marcin Lewandowski.

In the women’s 800m, Janeth Jepkosgei looks to steal back some of the limelight from her Kenyan teammate Pamela Jelimo who ran a sub-1:57 world lead last weekend. Jepkosgei’s 2012 best is 1:57.79.

Among those hoping to be pulled to a fast time are the British trio Marilyn Okoro, Emma Jackson and Jemma Simpson, all out to prove UK selectors got it wrong when leaving them out of the Olympic team.

Another Briton, Barbara Parker, will be one of the favourites in the women’s 3000m steeplechase. The US-based Parker broke the British record in Eugene.

Can Viljoen stand her ground?

Britons also feature heavily in the field events, not least the triple jumps where Phillips Idowu faces Christian Taylor, the man who took his world title in Daegu, and world indoor champion Yamile Aldama takes on world number one Olga Saladuha in the women’s event.

All eyes will be on Robbie Grabarz in the high jump where Canadian pair Mike Mason and Derek Drouin are his main threats, while Reese Hoffa leads a shot put field that includes Ryan Whiting, Tomasz Majewski and Dylan Armstrong.

Hoffa will have Christian Cantwell’s 22.31 world lead in his sights, while Barbora Spotakova aims to retake the women’s javelin initiative from Sunette Viljoen.

Viljoen beat the Czech world champion in New York throwing a South African record of 69.35 which remains the longest in the world this year. Goldie Sayers and Linda Stahl are also in the field.

Matthew Brown for the IAAF