But he went on to add that although the victory was good, the team must remain humble as they had more work to do ahead of the World Cup finals next summer.
The worldwide friendly game between Argentina and Nigeria gets underway at the Krasnodar Arena on Tuesday 14 November at 17:30 CET.
Nigeria's Super Eagles inspired by captain Mikel John Obi humbled Jorge Sampaoli's Argentina 4-2 inside the new Krasnodar Stadium in Russian Federation on Tuesday night.
"My biggest worry was the way the team played when we were behind".
Goals from Alex Iwobi, Kelechi Iheanacho and Brian Idowu gave the Eagles a much-needed victory ahead of the 2018 FIFA World Cup in Russian Federation.
Ever Banega curled in a free kick, awarded after Nigeria goalkeeper Daniel Akpeyi picked the ball up outside his area, in the 28th minute and Aguero finished off a sweeping counter-attack eight minutes later.
On resumption for the second half, Eagles up their game with skipper John Mikel Obi who was playing his 80th global game at the senior level for Nigeria spraying accurate passes.
Russia-based Bryan Idowu who was making his debut for Nigeria in the game made it 3-2 in favour of Eagles moments later when he latched onto a pass by Iheanacho inside Argentina box to deliver his debut goal.
The Manchester City striker was substituted at half-time, triggering a staggering collapse from the South Americans at the Krasnodar Stadium.
What time does the Argentina v Nigeria match start?