Matic has become a key player for United since joining the club from Chelsea for £40m earlier this summer, having played the full 90 minutes of all of United's games in both the Premier League and Champions League since completing his move.
Speaking on 'BT Sport' Gerrard said that he was amazed that Chelsea let Matic go, calling him on of the toughest players he has ever faced.
'He was one of the toughest opponents I played against. He is very leggy, he's good in the air, he competes, he always gets a toe in,' the former England international explained.
'He can run, he’s very aggressive with the ball and without the ball, he can burst past you with it and he can catch you.
'I couldn't believe it. I think out of all the Manchester United players I've seen them sign over the last couple of years, he's the one I thought "Oh no, I hope not" so very disappointed about that as a Liverpool fan.’
High praise from Gerrard but the towering midfeidler has earned all the plaudits coming his way so far this campaign.