The pre-tournament favourites stretched their unbeaten run to 36 games on Wednesday with Messi looking good over the 90 minutes.
Messi scored his team's fourth goal right before the break, having also set up Julian Alvarez to open the scoring in the 17th minute. Angel di Maria scored twice in between.
Argentina coach Lionel Scaloni made four changes at halftime but opted against resting his star player, leaving Messi on for the full 90 minutes.
Inter Milan forward Joaquín Correa scored the visitors' fifth goal on the hour mark.
Argentina start their World Cup against Saudi Arabia on November 22 before also facing Mexico and Poland in group C.
"We're confident," midfielder Rodrigo De Paul said.
"But for many it will their first World Cup so the first game will be very important."
Earlier, Andrej Kramaric's late goal was enough for Croatia to beat Saudi Arabia 1-0 in Riyadh.
Croatia star Luka Modric played only the last 25 minutes, enough to set up Kramaric for the winner in the 82nd.
Kramaric still had to elude five Saudi defenders before scoring his 20th international goal inside the far post.
Croatia coach Zlatko Dalic began with an unfamiliar line-up and gradually brought on his established players.
Chelsea midfielder Mateo Kovacic, Hoffenheim forward Kramaric, Tottenham midfielder Ivan Perisic and Real Madrid's Modric all came on in the second half.
Saudi Arabia's French coach Hervé Renard also made numerous second-half changes. His team have a tough task in group C against Argentina, Mexico and Poland.
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