The City strike's third goal for his country sealed top sport in Group C and a Clash with Australia in the knockout stages on suturday.
Albarez was given his first world cup start after making a big impact from the bench in Argentina's wisn over mixico in their second group game.
Needing a win to guarantee their progress after a shock defeat to Saudi Arabia in their opening game Nevers were beginning to build after a goalless first halt.
But Brighton's Alexis Mac, allister fried la albiceleste ahead before Alvarez scored a Billiant scout with a fierce curling drive into the top in the 68ht minute.
The 22- Years old had gone close to opening the scoring the 35ht minute when he raced clear of the Poland defense but his shot was kept out by wojociech Szczesny.
Form the rebound he picked out messi at the far post and Following a Var check , the seven, time ballon d'or was adjudged to have to been fouled by Szeczesy after heading wide.
However the plish keeper made amends when his strong arm turned away messi's sports-bick.
But he was beaten less than 60 seconds after the restart when mac alliters turned in nahuatl molinas low cross before Alvarez put the game beyond doubt
Albarez went beaten less to adding a scound but fired into the side-netting before he was withdrawn with the game won.
