Watch all the action from the Cheltenham Festival Friday

Watch all the action from the Cheltenham Festival Friday

It looks very much like it could be third time lucky for the eight-year-old who looks to be the flawless age and candidate to win a Gold Cup which is obviously missing a few high-profile stars.

But when Alan Potts, one cog in the merry-go-round of big owners on the move last autumn, took away a dozen horses from Henry de Bromhead, Harrington was, along with Tizzard, one of the main beneficiaries.

"He was running over two miles, but it was Robert who said he would stay and he did".

Harrington, who lost her husband Johnny to cancer in 2014, said to win the Gold Cup was on a different level to the other great successes.

So often in the shadow of Douvan over two miles, Sizing John kept on strongly up the hill to score by two and three-quarter lengths from the staying-on Minella Rocco (18-1).

"This is quite unbelievable", exclaimed former three-day eventer Harrington, the most successful female trainer in the history of the Cheltenham Festival, whose previous stable stars include Champion Hurdle victor Jezki (Ire) (Milan ) and Champion Chaser Moscow Flyer (Ire) (Moscow Society). But I had a lot of confidence in this horse. "When you're 25 you think you're going to win everything but I don't quite think like that these days".

"It's absolutely fantastic, my first runner in a Gold Cup".

Jonjo O'Neill's Minella Rocco (18/1) made late gains for second but the victor had flown, crossing the line two and three quarter lengths in front. In the day's penultimate race, Let's Dance justified favouritism to win the Mares' Novices' Hurdle and complete the four-timer.

The 70-year-old has also won a Champion Hurdle (with Jezki) and two editions of the Champion Chase (with Moscow Flyer) but the Grand National does not seem at the top of her priorities. The betting for the opening race, the Triumph Hurdle, is headed by Defi Du Seuil. "I can't believe it, I've got to get a Classic now [on the Flat]!" "I wasn't too anxious about the result because we have had such a good day anyway but Defi made it look easy", she said.