Monreal played with Zubimendi at Real Sociedad before hanging up the boots.
And he revealed via BetMGM ahead of the North London Derby, "Yes, I spoke with him (Mikel Arteta, Arsenal manager) and with the club in general a long time ago.
"I said to them: 'You need to look at Martin Zubimendi,' because for me, when I arrived at Real Sociedad, Mikel Merino, for example, had already played for Newcastle and Borussia Dortmund.
"He was already a good player, but Martin had come from the academy and had started from zero.
"Even from the beginning and from the first moment, you could see something different, you know, something special.
"You see this guy, he's 20 or 21 years old and he performs like he was already playing for 10 years.
"He had something different and in my opinion, it's been a really, really good transfer.
"Yes they paid a lot for him but he deserved it. He's still young and he's going to stay for the next six, seven, eight years, at his top level. It was a good move for Arsenal, and for Martin, of course."