Willo Flood admits it was a 'big shock' to make his Celtic debut in the starting line-up against Rangers.
The midfielder joined Celtic from Cardiff City before the close of the transfer window, having spent the previous 18 months on loan at Dundee United.
He was thrust into the Bhoys side for Sunday's 0-0 draw at Parkhead and Flood was overwhelmed to start the Old Firm derby.
"It was a big shock for me because I didn't really know where I stood in the manager's plans," Flood told Celtic View. "I've been at Celtic for a few weeks now, but I wasn't able to be involved in the last few games.
"To be honest, I was just hoping to be in the squad. I'd have been happy to be on the bench, so when the manager gave me the nod, I was really chuffed.
"I didn't even have time to tell anybody but, looking back, that was probably for the best. The manager just pulled me aside and told me I was starting on the right side of midfield.
"It was a massive boost for me. He has shown great faith in me and it's good to know that he believes in what I can do - he wouldn't have thrown me in against Rangers if he didn't trust me.
"I'll take a lot of confidence from that. It was one of the biggest games of the season so far and hopefully I can go on to bigger and better things from here on in."
The Irishman also revealed the experience almost reduced him to tears, saying: "Before Sunday, I had only ever watched the Glasgow derby at home on television.
"It was my first ever experience of the game, so to get the nod to start against Rangers was a dream come true for me, it really was.
"To just run out for the warm-up as a Celtic player was almost enough to bring a tear to my eye. It was a great honour to get that chance."