Without a slightly injured Lionel Messi, Ever Banega and Manuel Lanzini provided late goals for Argentina in a 2-0 win over Italy in a pre-World Cup friendly on Friday.
Italy will take on another World Cup-bound team, England, that same night in London.
But Lanzini made sure to place himself in even stronger contention for a place in Sampaoli's squad for the FIFA World Cup, taking a Gonzalo Higuain pass and superbly finishing past the legend Gianluigi Buffon in the 85th minute for Argentina's second goal.
"We played this game as a final", said Sampaoli, who is set to be without Angel Di Maria for next week's friendly against Spain after he suffered a thigh injury.
Having edged through to the World Cup thanks to Messi's treble in a 3-1 win over Ecuador in October, Argentina are focused on peaking in Russian Federation, where they will play Croatia, Iceland and Nigeria in the group stage. "We're on the right path", he said.
"We must realise this is a hard moment for the team".
The five-time world player of the year was named among 13 Argentina substitutes but, unbeknown to many in the stadium, there was no chance of him featuring.
In the 75th, Banega scored from the edge of the area in between three defenders after Italy's Jorginho gave up possession near midfield.
After the break, Caballero was the star as he twice denied Lorenzo Insigne before thwarting Ciro Immobile from close range.
According to British newspaper mirror.co.uk, Messi has been struggling for fitness since linking up with his global side before sitting as an unused substitute during Friday's 2-0 friendly win against Italy at the Etihad Stadium.