Hercules Wimbledon sprinter Rechmial Miller has vowed to come back fighting after suffering heartbreak at the IAAF World Junior Championships last week.

The 18-year-old was competing in the 100m final in Poland when he pulled up with cramp, and was forced to jog over the line in last place.

It was a bitter disappointment as Miller had impressed in the qualifying rounds, finishing second in his heat in 10.44 seconds.

He then upped the pace in the semi-final to clock 10.37secs running in the difficult outside lane, to get through to the semi-finals.

Miller, who was looking to build on his bronze medal in last year’s IAAF World Youth Championships and his silver in the Commonwealth Youth Games, said: “I did enough to qualify which is good, but I would have liked a bit more and I know I have more to give.

“It was the best start I have had in this competition, but my leg went and I couldn’t put it down.

“I knew I was in the mix and had the speed but it wasn’t meant to be.”

His father, Paul, a former Surrey 100m champion, who was in Bydgoszcz to support his son, said: “He suffered cramp, but we believe he should be fine to run again very soon.

“I was very pleased that Rechmial was able to get to the final of such a major competition.

“From the times he ran we know there is more to come before the end of the season.”

He added: “He is now in a position to compete and stay with the best in the world in his age group.

“This is a great achievement and he can only get better.”

Meanwhile, Miller’s 100m club record of 10.34secs has fallen to Theo Etienne, who clocked 10.23secs in an open meeting at Lee Valley.

At the same venue, Dwayne Cowan broke his own club 200m record in finishing second in 20.73secs to improve on his previous mark of 21.01 set in Florida in April.