Eddie Howe's side opened the scoring within four minutes of their friendly fixture at St. James' Park courtesy of Sean Longstaff's emphatic finish before Chris Wood's second-half penalty doubled the hosts' lead in front of 34,956 spectators.
Matt Targett's own goal halved the deficit in the closing stages before the Magpies saw out the contest as Miley - who made his first-team debut in last week's 5-0 win over Al Hilal in Riyadh - was introduced from the substitutes' bench.
The Stanley-born teenager, who signed a scholarship with United's Academy last summer, told nufc.co.uk: "It was a great feeling to get on the pitch and it was a good result. I really enjoyed it out there and also playing with the Academy lads too, such as Jay (Turner-Cooke) and Dylan (Stephenson) as well as the first-team players.
"It was a great experience to play with those who have competed right at the top level and it makes me want to continue doing that in the future.
"I was buzzing when I got called down the sideline to be brought on. I came on for Kieran Trippier and he told me to 'go and enjoy myself' which was great encouragement for me.
"I couldn't believe it, really. As a supporter of the club, I've watched the first-team play at St. James' Park nearly all my life so to be out there myself in front of so many fans was a great feeling. All of my family were watching, too, so that was even better.
"I suppose playing at St. James' Park feels a bit better but it was still a great feeling to play in Saudi Arabia and make my first-team debut. It was definitely the biggest crowd I've played in front of.
"It was a great atmosphere and I really enjoyed it. I've worked very hard over the years to get this point in playing for the first-team."
Miley, who made his international debut for England Under-17s in August, has trained regularly with the first-team this term, as well as travelling with the squad to Saudi Arabia earlier this month, and scored his first goal for Newcastle's second-string during a Premier League Cup tie against Sheffield United in November.
The young rookie, who won this year's Jack Hixon trophy for Tyneside's most promising youngster, is determined to build on his recent involvements with his boyhood club.
He added: "I've gained a lot of experience with the first-team recently. I'm getting some good tips from the senior players, seeing what they do on a regular basis.
"Having a taste of it does make me want more of it but I know I need to keep working hard to achieve more things like this in the future."
