Christian Malcolm's prospect of a gold medal at the World Indoor Championships in Lisbon this weekend have increased significantly with the news that his main rival has suffered a broken leg.

Coby Miller clocked 20.31 seconds, the world's fastest time of the year, when winning the United States trial in Atlanta but was then injured in a pile-up after the finish.

The 24-year-old American, who finished seventh at last year's Olympics in Sydney, has had surgery on a broken fibula in his left leg.

Malcolm, winner of last year's European 200m title, said: "It will make my chances of winning easier, but no-one likes to see anyone - even your biggest rival for a gold medal - miss the championships in circumstances like this."

Daniel Caines, another British medal prospect in Portugal, has also benefited from an American withdrawal.

Andrew Pierce, the fastest 400m man in the world this year with a time of 45.46 seconds, has opted to compete for Ohio State in the American College Championships instead.