Tierney, 23, has racked up 46 appearances for the Gunners since completing a £25million move from Celtic in August 2019.
The Scotland defender initially struggled to settle in at The Emirates, nevertheless, which he admits was a result of feeling “pretty nervous".
Tierney said: “I think he could see when I came that I was pretty nervous. I had the young boy look about me.
“You don't have much time to settle in. You are playing with big players and big names, so you have to hit the ground running.
“I remember that I probably overthought every mistake I made.
“I went home and was like, 'I could have done better, I could have done this'. Whereas I wish I had just relaxed a little bit more and enjoyed it.
“And that was the time Hector said to me, 'You're good enough to play here, just believe in yourself'. That helped me so much.
“It was after training in the changing room. Me and him had just done a gym session and after it we sat down for an hour and spoke.
“I think that changed everything. I went home that night feeling much better about myself.
“I went home that night feeling much better about myself. I remember texting him saying thanks so much for that chat, it helped me so much.
“I went in the next day with a different mindset, a different confidence and it was a big part to do with Hector."