Stimac played for Derby County and West Ham during a six-year spell in the Premier League.
He said: "At the moment, Bale is one of the top five players in the world. A fantastic, wonderful player.
"When I played in England, I played against Ryan Giggs and of course he was a good player too, world class.
"But I think Bale is better than Giggs. He has all of Giggs’s skills but he is stronger and he’s much more difficult for a team to deal with because of that."