Greene shines in Diamond League
World champion Dai Greene dispelled any doubts about his form and fitness with an impressive personal best in Paris on Friday night.
However, a seriously fast 5,000 metres race in the Diamond League meeting showed just how tough a challenge Mo Farah will face at the London Olympics.
Greene clocked 47.84 seconds, just 0.02secs outside Kriss Akabusi's 20-year-old British record, although it was only good enough for second place behind Javier Culson.
The Puerto Rican, who took silver behind the Welshman at the World Championships last year but is firmly the world number one this, won in a world-leading time of 47.78s to further enhance his claims for gold in London in a month's time.
But Greene's run was a welcome return to form following a slow start to the season caused by a knee operation he had over the winter and a bout of illness.
He was closing fast on Culson in the final stages, suggesting he will only get quicker as the summer progresses.
"PB tonight. Feels good to be back in business, all coming together at the right time. Ready for the big one." Greene said on Twitter.
Farah was not running in the French capital, but the 5,000m saw no fewer than 10 athletes go quicker than his previously world-leading time of 12:56.98.
Ethiopia's Dejen Gebremeskel won in 12:46.81 to become the fifth fastest of all time over the distance, while it was the quickest time since 2005.
His fellow countryman Hagos Gebrhiwet was second in a world junior record of 12:47.53 as the first six home all went quicker than Farah has ever gone.
World and Olympic champion Kenenisa Bekele, another Ethiopian, ran a season's best 12:55.79, but that was only good enough for ninth, meaning he is unlikely to run over the distance at the Olympics.
In the 100m, Tyson Gay, back after terrible injury problems, beat fellow American and former drug cheat Justin Gatlin to claim victory in 9.99s.
Gatlin is the third fastest man in the world this year with 9.80s, but he could not hold off the challenge of Gay, who powered through in the second part of the race to nick it on the line.
Gatlin, who served a four-year doping ban, was second in 10.03s, with home favourite Christophe Lemaitre third in 10.08s.
David Rudisha destroyed the field in the 800m, winning by over four seconds in a world-leading 1:41.54.
The race very quickly turned into one between the imperious Kenyan and the clock as he finished 0.53s outside his own world record.
Australia's Sally Pearson looks another athlete nailed on for gold in London after winning the 100m hurdles in a world-leading 12.40s, with Britain's Tiffany Porter finishing third.
Christine Ohuruogu ran a season's best 50.59s to finish fourth in the 400m as world champion Amantle Montsho won in 49.77s.
British record holder Shara Proctor had to settle for second in the long jump in 6.65m, Russia's Yelena Sokolova winning in 6.70m.
Steve Lewis was fourth in the pole vault, Lisa Dobriskey eighth in the 1500m and Barbara Parker eighth in the 3,000m steeplechase.