Hot favourite Inisherin could finish only fifth as Mill Stream emerged triumphant in the My Pension Expert July Cup at Newmarket.

Following a stunning display in the Commonwealth Cup at Royal Ascot last month, the Kevin Ryan-trained Inisherin was all the rage to beat his elders for the first time as the 11-8 market leader, but things did not go to script.

Art Power took the 11-strong field along for much of the six-furlong contest, closely pursued by Swingalong, and the latter had poked her head in front by the time she reached the final furlong.

In a race that turned into something of a scrap, Jane Chapple-Hyam’s 11-1 shot Mill Stream – third in the Queen Elizabeth II Jubilee Stakes at the royal meeting – was produced with a well-timed challenge on the far side of the track by William Buick, swooping late to deny Swingalong by a neck.

Vandeek, who suffered a surprise defeat at the hands of Inisherin in the Sandy Lane Stakes at Haydock in May before missing the rematch in the Commonwealth Cup owing to an unsatisfactory scope, shaped with plenty of encouragement in third.

Art Power boxed on to finish fourth ahead of the slightly disappointing Inisherin in fifth.

Chapple-Hyam said: “We were doing cartwheels when it rained, as it just took the sting out of the ground midweek. I think that is all he needs. He came here for a little bit of practice the other day.

“He’s never sparkling in his work, he just gets there but that’s him and as long as we know that, and William knows that, it’s fine, but he’s done it now, he’s got the Group One.

“You knew there was going to be a lot of speed and when they were doing 10 and change at halfway and he was sat in behind, I just knew he’d pick up and I’m thrilled.

“He likes it here, he’s been second here, so it’s nice to turn it round and get the win and he ran well at Ascot in third on very quick ground there.

“It’s nice to win here with it being my home track and my favourite track.

“I’m a very lucky lady to have Peter Harris as an owner, he knows the game and he believes in the horse too, so it’s good. It’s nice to join him and Gai (Waterhouse, who Chapple-Hyam had a winner for earlier in the day with Asian Daze) as a Group One-winning trainer.

“Peter has a good team in the yard, he supports them and he supports me, so to go and win a Group One for him, that’s what he wants and what the yard needs, so it’s good.

“He likes three weeks between races if you look back, so we’ll go to Deauville next for the Prix Maurice de Gheest, he’ll love the six and a half furlongs there – as a young horse, he got six there very well, so six-and-a-half, bring it on!”

Buick was completing a four-timer on the day after he previously enjoyed a treble for Godolphin and Charlie Appleby courtesy of Desert Flower, First Conquest and Ancient Truth.

The dual champion jockey was also securing the 100th Group One win of his stellar riding career.

He said: “He has been such a good horse for me this season. He is a Duke of York winner and ran well at Royal Ascot. We felt he had a bit more to give and Jane and the team convinced me he was a much better horse today – he duly was.

“That bit of rain really suited him and I was always so comfortable. He is really genuine and puts his head out. It was well deserved.

“This is my first July Cup and I’m absolutely thrilled.”