Liu Xiang's hopes of nailing the world indoor 60m hurdles title have received a huge boost with the withdrawal through injury of defending champion Dayron Robles of Cuba. The Cuban, reigning 110m hurdles Olympic champion and world record holder, injured himself hitting a hurdle in training in Spain. "Robles is suffering lower back pain and we don't want to take any risks, as the injury could worsen," Cuban athletics commissioner Aurelio Romero said. "We are in an Olympic year and don't want to risk anything as he is one of our hopes for London." Liu was the shock Olympic 110m hurdles champion in the 2004 Athens Games and remains history's second fastest man in the event. And the Chinese hurdler is coming into the March 9-11 World Indoor Athletics Championships here in top form, having clocked 7.41sec in Birmingham, England, to break the Asian indoor 60m hurdles record. But he followed that up with a false start disqualification in his next race in Stockholm, something the 28-year-old took as a timely reminder as to race tactics. "My feeling were mixed after taking part in two indoor meets in Europe," he said in a diary for the website of athletics' governing body, the IAAF. "I was delighted that I broke the Asian Indoor Record of 60m hurdles in Birmingham, England on the 18th of February, where my change from an 8 step start to a 7 step start has achieved initial success. "The thing that did bother me though is that I was disqualified because of my false start in Stockholm, Sweden on February 23rd. "But I think there was a silver lining for me that I was disqualified. It reminded me of my problems and shortcomings." Liu, who suffered the heartbreak of limping out injured from the 110m hurdles on home soil at the 2008 Beijing Olympics, added: "Mistakes in competitions are inevitable and it doesn't really mean so much to me. "More importantly for me is how to face it, accept it, pay attention to it, deal with it and let it go. "The key for me is to be more attentive and to solve it in the following day's preparation and training towards the upcoming World Indoor Championships in Turkey. "I have confidence in myself along with the determination and ability to solve this problem. We will see in Turkey this weekend." His main competition will now likely come from American pair Aries Merritt and Kevin Craddock. At the US trials, Merritt survived a pair of false starts by Dexter Faulk, who ran under protest following his first false start, to win the 60m hurdles in a time of 7.43sec. Craddock placed second in 7.46 ahead of two-time world indoor gold medallist Terrence Trammell and American outdoor record holder David Oliver. "It is what it is with the false starts happening, but you have to stay focused and do what you have to do," said Merritt, fifth at last year's 110m hurdles final at the world outdoor champs in Daegu, and fourth in the Berlin worlds in 2009. "Every time you run is not going to be perfect. There are going to be distractions, but you just have to race."