Following her impressive win in the Oaks at Epsom last month, she was supplemented for yesterday's race at a cost of pounds 25,000 to owner Bill Gredley, but had to overcome both the sustained challenge of Market Booster and a stewards' inquiry.
George Duffield pushed User Friendly to the front entering the straight but was unable to get away from Market Booster, who came with a smooth challenge under Michael Kinane with two furlongs to run, and looked sure to pick off the 8-11 favourite. But stamina is User Friendly's strongest suit and she kept on strongly to win by a neck, giving trainer Clive Brittain his first Irish Classic success.
'User Friendly quickened well off a furious pace, but the strong gallop probably won it for us in the end,' Duffield said.
Brittain, never frightened to aim high with his horses, said: 'User Friendly's long-term objective has always been the Arc in October, and we will not make any further plans for her until we get home and see how she is.'
While there was little doubt that User Friendly would keep the race in the stewards' room, Arrikala, who finished a close-up third, appeared to be an unlucky loser. Her jockey, Kevin Manning, caused the inquiry by trying to force his way through a non-existent gap between User Friendly and the rails throughout the final furlong.
Manning said: 'I just had to sit and suffer. The winner never strayed off the rail long enough to let me through. We were unfortunate, but I was instructed to keep Arrikala covered up and not to switch her wide as she tends to idle when she sees daylight.'
If Duffield joins the Green Party when he hangs up his riding boots, few will be surprised. Last season he won the Eclipse Stakes on board Environment Friend, and he has partnered User Friendly to both of her Classic successes this season. At the age of 46 he is on target to ride 100 winners in a season for the first time.
While the stewards in Ireland were content to let the result stand, their York counterparts played a major role in the outcome of the day's main betting race, the Magnet Cup.
Mr Confusion, ridden by apprentice Ollie Pears, passed the post a length clear from Tell No Lies, with Steerforth a further neck away in third. But Pears had persistently used his whip in his right hand, and Mr Confusion hung to his left, hampering Steerforth in the process.
Once the stewards had found Pears to be guilty of careless riding, they had no option but to place him behind Steerforth. The decision shocked Mr Confusion's trainer Steve Norton, who described it as 'diabolical', adding that he would be appealing.
Tell No Lies, trained by Peter Easterby, was the beneficiary. His rider, Mark Birch, also expressed surprise: 'I didn't think I would get the race but the rules were infringed for Steerforth.'
Lingfield yesterday staged the first ever televised all-weather contest. Jason Weaver, one of the season's leading apprentices, showed plenty of flair in sending 14-1 outsider Norfolkiev clear three furlongs from home, and never looked in danger of being caught. The world's largest bookmakers paid pounds 10,000 to sponsor the race. It was money well spent.