The final eight fixture will bring Chelsea ace Eden Hazard up against the star ability of Bale and according to Wales and Manchester United legend Giggs, his compatriot could be the deciding factor in the contest.
"Belgium are a team of talented individuals. They have talented players all around the pitch but Wales faced them in the qualifying group," Giggs said on ITV.
"The difference between Bale and Hazard is that Bale doesn't need to play well to be the match winner. He could score a header or a free-kick.
"But if Hazard doesn't pay well, he doesn't really impact the game. Bale is just being himself. He's comfortable with his mates and he looks it on the pitch.
"He's at home playing in this Welsh team and it's brilliant because he's one of the few in the world that you just cant stop.
"On his day, there's nothing you can do."