by Brendan Cole

Derval O’Rourke missed her women’s 100m hurdles semi-final while Deirdre Ryan finished sixth in the high jump at the World Track and Field Championships in Daegu, South Korea.

There was disappointment for Leevale athlete O'Rourke as she was not fit to start the race due to a calf injury she sustained during the first round, in which she finished second to Australia's Sally Pearson.

O'Rourke received treatment for the injury and an Athletics Ireland statement said she, "tested it out during warm-up today for the semi-final but as it was not 100% she made the decision to withdraw".

Pearson was the fastest qualifier from the semi, winning the second of three races in a brilliant 12.36. Naturalised Great Britain athlete Tiffany Porter (12.56) won the third semi-final and was second fastest in a new national record.

Pearson went on the win the final in a superb Championship record 12.28 with Porter finishing out of the medals after stumbling during the second half of the race.

Ryan jumped superbly before bowing out of the high jump final. The 29-year-old cleared her first height of 1.89 metres at the second attempt. She then cleared 1.93m on her first attempt but missed three times at 1.97m, just clipping the bar with her third effort.

She finished in sixth place overall with Russia's Anna Chicherova beating Blanka Vlasic of Croatia in the battle for gold.

Neither woman could clear 2.05m but Chicherova's perfect record up to 2.03m saw her deny Vlasic a third consecutive title. Antonietta Di Martino of Italy cleared 2.00m on her third attempt to claim bronze.

A new Irish record was set by Ryan earlier in these Championships at 1.95m. That jump means she has reached the 'A' qualification standard for the London 2012 Olympics.

Ciaran O'Lionaird ran well (3:37.81) but could not get involved in the shakeup in a hot men's 1500m final and finished 10th.

O'Lionaird was sixth at the bell and most of the field was still in touch rounding the final bend, but Kenyan duo Asbel Kiprop and Silas Kiplagat separated themselves and battled for gold in the last 50 metres. Kiprop (3.35.69) came out on top in a tight finish with Kiplagat taking silver.

A strong finish from Matthew Centrovitz of the USA saw him overtake several runners in the closing stages to take third.

Earlier in the day, Colin Griffin was disqualified from a 50km walk race won by Russia's Sergey Bakulin.

The Ballinamore AC man was placed in 31st position when he received his third red card. The event saw a number of high profile disqualifications as the sport's tough rules were strictly enforced.

The result was hugely disappointing for the Leitrim man who has been training in tough conditions at altitude in Italy in preparation for these Championships.

Russian athletes finished in first and second.

Bakulin won gold in 3 hours 41 minutes and 24 seconds from Denis Nizhegorodov, 3:42.45, with Australia's Jared Tallent two minutes back (3:43.36).