Punters are backing Rachael Blackmore to land a second Randox Grand National, with her mount Ain’t That A Shame rocketing to the top echelons of the market for Saturday’s Aintree showpiece.

Blackmore created history two years ago when steering Minella Times to victory, becoming the first woman to ride the winner of the four-and-a-quarter-mile marathon.

Like Minella Times, Ain’t That A Shame is trained by Henry de Bromhead.

The nine-year-old registered his first chase success at the seventh time of asking at Gowran Park last month, with the form subsequently boosted when runner-up Macs Charm scored at Fairyhouse on Monday.

Having been as long as 16-1 with some firms on Friday morning, he halved in price by the afternoon.

And Blackmore feels he has the right credentials to run a big race in the National.

“Ain’t That A Shame has a lovely profile for the race,” she told her Betfair blog.

“He was unlucky to be just beaten in the Munster National at Limerick in October, and it wasn’t my best day in the saddle when I finished fourth on him in the Paddy Power Chase at Leopardstown over Christmas.

“But he won nicely at Gowran the last day, and it was no harm that the runner-up came out and won at Fairyhouse there at the weekend.

“You don’t really know how a horse will handle the track or the fences until you get out there, but he had a pop over the National fences at the Curragh, and he went well. I’d be confident that he will take to the fences fine.

“He travels well through his races, which is a big help. You’re just hoping that you can get into a nice position and find a nice racing rhythm over the first few fences. I am hopeful that he can.

“After that, you never know, it’s the Grand National, but he has his chance and I’m very much looking forward to it.”

Speaking further after riding Inthepocket to victory in the Minella Times colours on Friday, Blackmore added: “Everyone who is down at the start is in with a chance, that is the kind of race it is. It is really exciting to be part of it and on such a good horse and I can’t wait.

“I never really felt much pressure in the race in the first place. It is just a race that everyone knows there are so many different things that can happen. You might be on the favourite, but it is not like riding the favourite in the Champion Hurdle. It doesn’t carry the same pressure as there are so many different variables in the Grand National.

“You are delighted to be down there and I will give it a crack and see what happens. It is a different atmosphere in the weighing room. Everyone is wishing each other good luck. It definitely has a different feeling to any other race that I’ve ridden in.

“He has a really good profile for the race and he is a very exciting horse to ride in it. He did (run in the same race that Minella Times ran in before winning the Grand National at Leopardstown) and I maybe didn’t give him the best ride in that race and he finished fourth. There is definitely more to come from him.”

Ain’t That A Shame runs in the colours of Brian Acheson’s Robcour — but he seemingly does not share Blackmore’s optimism, saying: “I don’t know where the money is coming from. I really don’t, he’s useless, genuinely, he’s useless!”

De Bromhead also saddles Gabbys Cross, who was third in the Leinster National at Naas when ridden by Blackmore.

Peter Carberry renews the partnership this time and the trainer said: “I think we’ve two live chances with Gabbys Cross and Ain’t That A Shame.

“They are both in good form and hopefully they can give a good account of themselves.”

Bookmakers are attributing the welter of cash to Blackmore’s popularity.

Nicola McGeady of Ladbrokes said: “The ‘Blackmore effect’ appears to be sweeping the nation as everyone seems to be getting behind Ain’t That A Shame in the Grand National.

“Blackmore made history by becoming the first woman to win the famous race two years ago and the public are backing her to repeat that feat. As bookmakers, it’s certainly a result we are praying to avoid.”