O’Sullivan ran a fine race and was only edged out in the final 100 metres by American Amy Rudolph, who clocked 32 minutes 16 seconds.

“She had just a little more finishing speed than me,” said O’Sullivan.

“It was important that I ran well here and I achieved that aim. I’m more than happy with how things turned out, to run so quickly at this stage of my marathon training and with plenty of mileage in my legs, proved my preparations have gone well.”

It shows O’Sullivan has made giant strides since a difficult training camp in Australia after a spell injured.

“Sonia was just back from injury and finding it really hard,” said Australian training partner Craig Mottram, winner of the men’s race in Dublin for a third successive year.

“But she stuck in and showed the determination which has made her such a great athlete. Mark my words, she’ll go well next week.”

O’Sullivan and fellow Irishwoman Jolene Byrne were involved in a thrilling battle with Rudolph in the final kilometre of the race.

However Rudolph, who is marrying Mark Carroll – holder of the Irish 5,000m and 10,000m track records – in October, had just enough.

The highly experienced Olympian finished third in the USA’s 8K national road running championships two weeks ago and had expected to improve on that New York performance.

“I knew I was in good shape,” said Rudolph, who smashed O’Sullivan’s course record by eight seconds despite the blustery conditions.

“I felt really strong, but when Sonia made the break at 600m, I was hanging in and at one point thought she had me.”

O’Sullivan was upbeat, her own quick time confirming that she is in shape before taking to the streets of London next weekend.

She said: “That was a really hard run, just what I wanted against the best-ever field here.

“With a kilometre left, any one of three of us could have won it.

“I probably hit the front a little earlier than I should have done and really, I wanted to wait nearer to the finish.

“But I could feel the pair of them breathing on my neck, so I went. It really was a competitive race and I’m pleased it went so close to the wire.”

Mottram’s success came after he finally shook off an unexpected challenge from Chris Davies, who dogged him for almost seven kilometres of the race.

“I didn’t know who he was, but in fairness he ran a very strong race,” said the world’s top non-African distance runner.

“Eventually I did push well clear – but all credit to him for making it much harder than I thought it would be.”

Davies himself was delighted to run so well after the Telford postman had a horrific accident delivering mail last July.

“I thought at first I had broken my back,” said the British international. “I didn’t start training again until last November.

“Today was a great race for me and I couldn’t have wished for a better comeback at this level.”

Davies clocked 29min 07sec, 27 seconds slower than Mottram, whilst Mark Miles surprisingly outsprinted John Mayock by two seconds to clinch third spot in 29min 26sec.