Britain's Liz Blatchford was the runaway winner of the Great Liverpool Triathlon on Sunday.
Dillon admitted she was feeling jaded after the Olympics
Blatchford blitzed the field, finishing in one hour, 54 minutes and 56 seconds - more than a minute ahead of nearest rival British Olympian Michelle Dillon.
Dillon, who clocked 1:56.25, was aiming to defend her crown, but it was a tough task so soon after finishing sixth in the searing heat of Athens.
Blatchford now wants to represent England at the 2006 Commonwealth Games.
Blatchford - formerly a resident of the Gold Coast in Australia - narrowly missed out on selection
for Australia's Olympic team and has now decided to switch allegiance.
"I took out dual nationality in June," said the runner-up at this year's London Triathlon.
"My mum Ann is from Salford while my father Mike was born in Inverness, but
it was still a hard decision to make.
"I was always
ranked third or fourth in Australia but didn't perform well in the Olympic
selection race so decided to make the change."
Dillon posted the fastest 10km run of the day - a time of 35mins 7secs - and that lifted her from sixth position after the 1,500m swim and 40km bike ride, to second place.
But she admitted she did not have the reserves to catch Blatchford.
"There's still a bit of Athens in my legs," admitted Dillon. "The race was
only 10 days ago.
"I was absolutely shattered and knew reaching Liz would prove to too much," she said.
In the men's race, Tim Don, who finished 18th in Athens, was in good enough shape to win in 1:48:27.
He conserved his energy until the final 600m when he sprinted away from Stuart Hayes.
Richard Stannard took the
bronze-medal in 1:49:40, while Andrew Johns, who finished two places ahead of Don at the Games, could only manage 1:52:46 for seventh place.