The admirable Creggs Pipes cut out the running for much of the 10-furlong showpiece but having set a furious pace, she predictably folded in the straight. Zhukova hit the front inside the final two furlongs, but Nezwaah ranged alongside soon after and the further she went, the better she looked.
Rain Goddess came from out of the pack to try to lay down a late challenge, but Nezwaah was not for catching and was comfortably on top at the line.
The big disappointment of the race was 15-8 favourite Journey, who beat only the fading Creggs Pipes home.
Atzeni said: "She was very impressive and travelled beautifully.
"She was a little bit slow into her stride. When I took the blindfold off she stood there for a couple of strides, but she travelled beautifully into the race and picked up really well.
"I got quite a smooth run and just had to wait to get a gap.
"Two days ago we didn't know if she was going to run or not because of the weather, but Roger felt the ground was going to be fine for her and she's proved him right."
Varian said: "We're delighted with her and she's always promised a lot.
"We thought we'd come here and have no excuses as the ground had dried out. We would have been a bit worried if the ground had been on the soft side, but it dried out nicely for her.
"We've always thought a lot of her, thought she should run well today and we'd really learn how good she was. I'm delighted she's won and I'm really grateful to Sheikh Ahmed (al Maktoum, owner) for being so patient with her.
"I think there were four previous Group One winners in the race. You could probably name a small handful of very good fillies that aren't here, but still it was a good race on paper and none of these Group Ones are easy to win.
"It's a thrill to win one and a great thrill to get this filly winning at the top level because we've always loved her."
Discussing future targets, the trainer added: "We'll get her home and see if she's fine and speak with connections.
"She's well entered up. She's in the Nassau Stakes, the Beverly D at Arlington. She's got all the big entries and we thought how we ran today would perhaps determine where we went.
"Maybe she's justified staying in Europe and taking her to Goodwood for the Nassau. We'll see."
Aidan O'Brien said of the runner-up Rain Goddess: "We're delighted with that. It was her first time at the trip and she saw it out well."