Cycling Tour of Britain: Philip Deignan showed his huge potential when he finished a fine 18th overall in the Tour of Britain yesterday, clearly the best amateur in the race despite being just 20 years of age.

On his form over the past five days, the Letterkenny man will start the Under-23 World Championships in Verona next month as one of the favourites.

Deignan placed 19th on Saturday's penultimate leg, cresting the uphill finish at Celtic Manor in Wales some 13 seconds behind race leader Mauricio Ardila (Chocolade Jacques), who outsprinted Relax-Bodysol rider Fernandez Moreno to win the stage.

Yesterday, Deignan finished safely in the main bunch while his Grant Thornton Ireland team-mate David McCann spent much of the 72.4-kilometre London criterium in a four-man breakaway that included British triple Olympic medallist Bradley Wiggins.

Despite a brave effort, this quartet was reeled in with two laps to go.

Waterford's Ciarán Power (Navigators Insurance) galloped home a fine sixth in the sprint finish behind the day's winner Enrico Degano (Barloworld). Double Tour de France stage winner Tom Boonen (Quick.Step-Davitamon) finished fourth.

While Deignan fell short of breaking into the top 10 overall, as he had hoped, the performance is still a highly encouraging one for him. After five stages and 804 kilometres of racing he finished just 41 seconds behind Ardila, and ahead of many well-known professionals.

Another 20-year-old, Tim Cassidy, was 34th, one place ahead of Power, and he too should be prominent at the under-23 championships.

"I'm very happy," said Deignan afterwards. "I felt good, even though I think I was a little bit below form coming into the race as I was sick after the European Championships. Hopefully I will ride well in the World Championships. If I can keep this form, I should have a chance of a medal."