James Dasaolu becomes second-fastest Briton in history

James Dasaolu clocked an astonishing 9.91 seconds in the 100m semi-finals at the British Championships to become the second fastest Briton in history.

In warm and still conditions, the 25-year-old broke the championship record with one of the fastest times of 2013.

Dasaolu's time has only been bettered by former world and Olympic champion Linford Christie's 9.87secs - in 1993.

Dai Greene, Rhys Williams, Asha Philip, Tiffany Porter and Christine Ohuruogu qualified for the World Championships.

But it was Dasaolu's performance which took the breath away as the Briton produced a time which suggested he might, one day, achieve his aim of breaking the American-Jamaican duopoly in the sprints.

His fourth personal best this year before a stunned crowd at Birmingham's Alexander Stadium was three-hundredths of a second faster than Jamaica's six-time Olympic champion Usain Bolt has managed this year.

Tyson Gay (9.75), Asafa Powell (9.88) and Justin Gatlin (9.89) are the only sprinters to have covered the distance quicker in 2013.

"I knew I was going to run quick from the first step," the Loughborough-based athlete, whose previous record was 10.03secs, told BBC Sport.

"Once you get to 60-70m, your body is running as quick as it can and it's all about relaxation. Because I was so far ahead it was much easier to relax."

Indeed, Dasaolu looked at the clock and raised his arms in disbelief as he comfortably finished ahead of a field which included Mark Lewis-Francis.

He now joins Christie, Dwain Chambers and Jason Gardener on the list of Britons who have dipped under the 10-second barrier in the 100m.

"As a sprinter, you want to go underneath 10 seconds and I'm happy to do that," added Dasaolu, whose early career had been hampered by injuries.

"Sub-10 is a big thing for me and I just hope to continue running sub-10s. I'm happy with 9.91 and I just want to build on that."

Dasaolu, however, withdrew from the final after experiencing cramp following his win.

"My ultimate aim is to be fit for Moscow and I don't want to risk an injury competing in the final," explained the sprinter who, despite not winning the 100m title, is certain of his place when the British team is announced on Tuesday because of his blistering form this season.

In Dasalou's absence, 35-year-old Chambers collected his seventh British title - and secured his place in the British team for Moscow - by winning the final in 10.04 seconds.

The Championships serve as trials for the World Championships, although the winner of each event will only be selected provided they have also met the 'A' standard set by UK Athletics.

As a reigning world champion, Dai Greene did not have to worry about qualifying for Moscow but he did ease fears over his form and fitness by winning the men's 400m hurdles.

In a close finish, the 27-year-old was neck-and-neck with compatriot Rhys Williams over the final hurdle before pulling ahead on the home straight in a season's best 48.66secs.

Greene's wildcard entry for Russia means Williams, by finishing second in a personal best 48.85 secs, has also earned a place on the British team.

Meanwhile, 2008 Olympic champion Ohuruogu (50.98) comfortably won the women's 400m.

A personal best 11.20secs saw Asha Philip become women's 100m British Champion, while Porter - who had already achieved the 'A' standard - won the women's 100m hurdles.