Adam Wainwright proved he has both a golden arm AND golden pipes on Thursday ... the Cardinals star pitcher sang the National Anthem for his team's Opening Day ceremonies -- and crushed it!!
St. Louis tapped the injured right-hander for the awesome honor just before the Redbirds took on the Blue Jays at Busch Stadium ... and check out video of his performance -- he proved he can saaaang!!!
The 41-year-old seemed very comfortable on the mic ... hitting every note as the crowd in the stands went wild.