Rory McIlroy celebrated making a fantastic start to the "fiddliest" Open of his career as his delayed return to St Andrews proved well worth the wait. America's Cameron Young held the lead thanks to firing eight birdies in a flawless 64, a score only McIlroy himself has beaten in the opening round of an Open Championship on the Old Course. McIlroy's 63 came back in 2010 and was followed by an 80 in terrible weather, while an ankle injury suffered playing football prevented him from bidding to retain the Claret Jug at the same venue in 2015. The four-time major winner admitted this week therefore felt like the title defence he never had and he enjoyed an ideal start, holing from 55 feet for birdie on the first and making seven in total in his 66, the same score he shot to begin his wire-to-wire victory at Hoylake.