Our record goalscorer was substituted just before the hour in Brasilia but, in a game of few chances, went agonisingly close to grabbing the opener with what would’ve been his 42nd strike for La Albiceleste.
Aguero pounced after an early defensive mix-up in the Paraguay defence but his instinctive effort on the turn dropped agonisingly over the bar.
Instead, the honour fell to Papu Gomez, who latched onto Angel Di Maria’s clever reverse pass in behind and dinked over the onrushing Antony Silva on ten minutes to grab the game’s only goal.
The match in Brasilia also represented a significant landmark for Argentina, with talismanic captain Lionel Messi making a record-equalling 147th international appearance.
And the Barcelona captain almost marked the occasion by doubling the lead, rifling a vicious free-kick inches wide of the far post before the 20-minute mark.
Despite their best efforts, both sides were limited to a series of half-chances across the remainder of the match, but it was enough to guarantee Argentina’s place in the knockout stages.
Aguero and co. are top of Group A with an impressive haul of seven points from their opening three matches.
And our leading marksman will be vying to reach a century of appearances when they lock horns with Bolivia on Tuesday 29 June.
Chile have also qualified for the quarter-finals, sitting second in Group A on five points, while Paraguay’s defeat to Argentina leaves them third with three points from two matches.
Uruguay’s solitary point leaves them fourth, while Bolivia are rooted to the foot of the table after losing both of their opening matches.