The Dublin-born youngster and Irish youth international is a Celtic fan so the chance to play in the friendly was good enough.
But he was also cheered by the fact that his nan and grandad, Hilda and Tony, managed the trip from Ireland to cheer him on.
And Mark certainly let no-one down as we held our own until two goals in eight minutes in the second half saw the Scottish champions home.
Indeed, in-between those goals on 60 and 68 minutes, Mark came closest to replying for us with a shot against the woodwork.
"Most Irish boys like Celtic and it was a dream to play at Celtic Park," beamed the 19-year-old forward back at Spurs Lodge this afternoon.
"My nan and grandad were over as well and that made it even more special for me. My grandad comes to watch me quite a but but not my nan. That was fantastic.
"It was just great to be out there and even better to play the full 90 minutes.
"A lot of young players got a chance and I thought we went out and did well. We did well up to half-time and the goals they scored weren't great from our point of view.
"Celtic had a decent side out and if that side started in the Scottish League, it would do well.
"A few of the younger boys had a feeling we might play because it's Liverpool on Saturday and we don't want any more injuries. I had a feeling I would be in the squad but to play the full game was brilliant, an unbelievable experience."
It was a family affair as Mark Yeates fulfilled one of his footballing dreams at Celtic last night.