David Rudisha cruised into the semi-finals of the men's 800m on Friday but kept mum on the Kenyan coach sent home in disgrace after having tried to impersonate an athlete for a doping test.

Sprint coach John Anzrah offered a urine sample in place of 800m medal hope Ferguson Rotich, who finished fourth in last year's world championships in Beijing.

Anzrah was immediately sent home by the Kenyan Olympic Committee, but with no action having yet been taken against Rotich, the 800m runner competed in Friday's heats and duly qualified for Saturday's semi-finals.

Rotich did not linger long under the eye of the media, sprinting past awaiting journalists after his race.

A third Kenyan, Alfred Kipketer, also shook off questions.

"I don't know, I don't know," a flustered Kipketer answered when asked about the Rotich situation.

Rudisha fired out a warning to rivals on the track at the Olympic Stadium, pulling away at 600m to clock the fastest qualifying time of 1min 45.09sec and will be joined in the semi-finals by a host of favourites including Djibouti's Ayanleh Souleiman, Bosnian Amel Tuka, Poland's Adam Kszcot and American Boris Berian.
Botswana's Commonwealth champion and 2012 Olympic silver medallist Nijel Amos, however, failed to make the cut, fading down the home stretch to come in 5sec down on the lead time.

"It was good," said Rudisha, whose world record, gold medal-winning run at the London Games was one of the performances of those Olympics.

"It was just cruising to qualify for the semis tomorrow, which is main part of the competition as you have to secure your place in the final.

"I'm in good form, there's no doubt about that. I'm very confident because I'm finding my finishing power in the last 100m, so I think I'm in a position to control my races again."

Rudisha admitted to feeling the pressure of defending his title over the two-lap race.

"There is a lot of pressure, of course, coming here as defending champion, as a world record holder and as a world champion. There's a lot of expectation," he said.

"Last year and this year are completely different. I feel like I'm in better form, almost like my good years between 2010-12.

"My training's been going well. I haven't been performing well in some of the races I've had.

"I had a bad start in Shanghai, I came to Stockholm in bad weather. It only improved in Birmingham in the 600m and Budapest where I ran the world leading time."

Source: Arab News