The 19-year-old daughter of singer Chris De Burgh has been the subject of sustained betting which has seen her odds cut from 10-1 to 4-1 in the past few days. Other hotly tipped contenders include Miss China, Miss Norway, Miss Canada, Miss Venezuela, Miss Georgia and Miss South Africa.
Ladbrokes UK spokesman Warren Lush said yesterday: "Being Chris De Burgh's daughter must help Miss Ireland. The question many are asking is whether she'll be a lady in red. Rosanna has been the subject of the biggest gamble in recent years and we'll be in the red if she triumphs."
Former Miss Ireland Andrea Roche is equally convinced that Rosanna will take the Miss World crown. "She is used to meeting famous people and is very poised even though she is only 19 years old. She is very mature, very bright and oozes confidence. She is also, of course, extremely beautiful. Rosanna is almost six feet tall with long blonde hair and a Hollywood smile to match."
Rosanna herself was being a little more cautious last night about her chances. "I can't think about the odds on me winning right now. I just want to get on and do my best, but I am delighted with all the support I have got from my family and friends."
Ms Roche also dismissed as "utter rubbish" British tabloid speculation that Rosanna had provoked jealousy among her fellow contestants by winning two ancillary Miss World competitions this week (the beach and swimsuit competitions). "She is a lovely girl and everyone likes her. She is rooming with Miss Canada and already the two girls are like old friends."
Irish bookies have also slashed the odds they are offering on Rosanna. Leading bookmakers, Paddy Power, said there had been an "absolute flood of money" placed on Miss Ireland over the past few days.
"She opened up at 9-1 two weeks ago and she's now shot up to 4-1," said a spokesman. "She's been astonishingly popular it's quite exceptional to see such a one-way tide of money."
He confirmed that the renewed interest in Miss Ireland had begun when she won the beachwear contest earlier this week.
But while other favourites Macedonia, Georgia and Bolivia, are pulling in the money, it's peanuts compared with Miss Ireland, he said.
Ladbrokes in Ireland reported a similar story. "In the industry we would say it's a one-horse book for us but in this case it's a one-girl book," said spokesman Rory O'Carroll.
"Her odds have just been slashed to 4-1 in the last two hours and it looks like she's got a very good chance of winning."
He also said that the surge of interest appeared to have come off the back of Ms Davison's win in the Miss Beach contest last week.
Mr Carroll said if Miss Ireland wins, they'll be paying out over E50,000 this weekend.
The 106 girls battling it out for this year's Miss World title are preparing for the final countdown to be held tonight in Sanya, on the island of Hainan, China.