Alvarez opened the scoring in the 13th minute thanks to some terrific work from Lautaro Martinez, who was able to snake his way into the box, beating multiple defenders to get to the touchline and drag one back along the edge of the six-yard box for a simple tap-in.
Argentina continued to create half-chances throughout the remainder of the first half, and it was more of the same to begin the second 45, with Martinez going close after a slick one-touch pass from Alexis Mac Allister gave him some space inside the box, but he pushed his shot wide of the far-post.
Lionel Messi was subbed on in the 56th minute, and just 10 minutes later he had his first chance after a one-two on the edge of the area allowed him to break into the left-hand side of the box, but his shot from a sharp angle was easily thwarted at the near post.
But fans in attendance would get what they came for in the 87th minute, when Messi picked up a deflected pass just outside the penalty area and fired his left-foot shot hard and low across his body into the bottom-right corner.
Just two minutes later Argentina were awarded a free kick in the same spot, and Messi again converted, this time around the wall into the bottom-left corner.