The 19 year-old singer -- wearing a black shirt and matching pants, his hair swooped up into a pompadour -- plucked out the soul-stirring tune's familiar groove on his acoustic guitar.
With a spare set that kept the focus firmly on his swoon-inducing vocals, Mendes had the crowd up on their feet singing along to his infectious hit -- including apparent super fan Keith Urban, who clearly knew every word. Mendes then sent those true believers into a frenzy of shrieks when he wandered out to a second mic stand in in the middle of the floor for a big finish to the number.
Watch below:
