The two goliaths went head-to-head in classic match play fare. And when Stuart Grehan, the Amateur champion, sank a 15-footer for birdie on the 18th hole to take out Preston Stout, the world number one, in the top singles it led to choruses of Óle Óle Óle from those gathered around the green in acknowledgement of the man’s contribution to Great Britain & Ireland’s first-day effort against the United States in this 51st edition of the Walker Cup.Grehan’s heroics – three down to Stout through three holes, back to level through 10 but two down standing on the 16th tee, only to finish birdie-birdie-birdie for a remarkable one-hole win – were crucial in painting the picture of the first day’s play, as GB&I took a one-point lead 6½-5½ – from day one into Sunday.The fickleness and magic of match play captivated the 8,000 sell-out galleries who traipsed over the dunes and behind and alongside the players on the fairways.Grehan’s singles take out of Stout laid down a marker, but the Americans, looking for a sixth straight win in the Walker Cup, responded brilliantly and took the next four singles – with wins by Ethan Fang, Will Jennings, Jay Leng Jnr and the veteran Stewart Hagestad – to quieten the crowds.Then, it flipped back to GB&I’s favour, with a superb back-end effort that saw Luke Poulter, Niall Shiels Donegan (two from two for a 100 per cent record) and Eliot Baker win their singles. The upshot was that the first day’s singles finished 4-4 which, combined with the home team’s 2 ½ to 1 ½ advantage from the morning foursomes, meant a 6 ½-5 ½ first day result.So, advantage GB&I in their quest for a first win since the 2015 success at Royal Lytham & St Annes.Grehan was immense in his first day’s play, partnering Baker to a halved match against Stout and Fang in the top foursomes and then demonstrating brilliant shot-making and mental fortitude in turning his singles match with Stout around to close out on the 18th for a thrilling win. The two players shared 15 birdies between them.Afterwards Grehan revealed he had suffered a family loss earlier in the week with the passing of his uncle, Willie Egan.“Maybe he was looking over me, I guess. He was very good to me,” said Grehan, who retained a calm demeanour throughout his rollercoaster match with Stout.There was never any panic. Not even when he lost the opening three holes. “I was very, very focused, very calm. I knew I’d have some chances, but to kind of produce the golf I did, I’m just very proud of myself,” said Grehan, who has revelled in the role of being the on-course leader inspiring from the front.As GB&I captain Dean Robertson observed of the decision to front-load Grehan, “He’s the Amateur champion!”Morning Foursomes: GB&I 2½ USA 1½Stuart Grehan/Eliot Baker halved with Preston Stout/Ethan FangConnor Graham/Tyler Weaver bt Jay Leng Jnr/Kihei Akina 1 holeLuke Poulter/Sam Easterbrook lost to Miles Russell/Tyler Watts 1 holeNiall Sheils Donegan/Josh Hill bt Josiah Gilbert/Ryder Cowan 4&3Afternoon Singles: GB&I 4 USA 4Stuart Grehan bt Preston Stout 1 holeJack Whaley lost to Ethan Fang 1 holeConnor Graham lost to William Jennings 1 holeTyler Weaver lost to Jay Leng Jnr 2&1Ben Bolton lost to Stewart Hagestad 2&1Luke Poulter bt Miles Russell 2&1Niall Sheils Donegan bt Tyler Watts 3&2Eliot Baker bt Josiah Gilbert 3&2.Day one result: GB&I 6½ USA 5½Sunday foursomes pairings8.05am: Stuart Grehan/Eliot Baker v Preston Stout/Ethan Fang8.20am: Luke Poulter/Sam Easterbrook v Jay Leng Jnr/Kihei Akina8.35am: Tyler Weaver/Connor Graham v Miles Russell/Tyler Watts8.50am: Niall Shiels Donegan/Josh Hill v William Jennings/Ryder Cowan