The 29-year-old's composure on the ball, ability to pick a pass and tough tackling paid dividends at both ends of the pitch in the must-win game against Nigeria.
Lionel Messi and Marcos Rojo may have grabbed the headlines after scoring in Argentina's 2-1 win over Nigeria on Tuesday, but it was the decision to start Ever Banega in midfield that arguably had the biggest impact on Jorge Sampaoli's team.
Victory sent Argentina into the knockout stages at the expense of their opponents and the manner in which they achieved it, scoring a late winner when all looked lost, offered a much-needed boost after the struggles in their first two games.
Held to a 1-1 draw by Iceland and thumped 3-0 by group winners Croatia, Argentina were hanging on by a thread coming into the Nigeria match, having proved they were vulnerable in defence and struggling to get Messi on the ball.
The South Americans were overrun by Croatia, with Javier Mascherano and Enzo Perez chasing shadows in midfield as Croatia's Ivan Rakitic and captain Luka Modric ran the game in the middle of the park and ripped Argentina to shreds.
Messi got fewer touches in that match than Willy Caballero in the Argentina goal.
Sampaoli's solution was to hand Banega his first start of this World Cup against Nigeria and the 29-year-old's composure on the ball, ability to pick a pass and tough tackling paid dividends at both ends of the pitch.
It was his pinpoint ball over the top from midfield to pick out Messi that led to Argentina's opener in the 14th minute and he bailed out the hapless 34-year-old Mascherano, who looks well past his prime, on more than one occasion.
Banega's instinct to shield the ball and wait for the right moment brought Messi into the match to a far greater extent and, with their talisman involved once more, Argentina duly prospered.
The Sevilla midfielder's chequered past dovetails nicely with Argentina's affinity for the footballing anti-hero, a role best exemplified by Diego Maradona, who is loved back home as much for his his unpredictable temperament as for his ability.
If Messi is less loved by Argentina fans than Maradona because of his perceived lack of passion, as some suggest, the 29-year-old Banega is the perfect foil.
His catalogue of misfortunes include being run over by his own car while his misbehaviour, ranging from drink-driving to getting sent off for abusing a referee, may have been a factor behind his omission from the World Cup squad four years ago.
"A coach who has to train Leo knows everybody surrounding him needs to make him feel secure, and if we're able to create passes to Leo we can create opportunities because otherwise we suffer," Sampaoli said after the win in St Petersburg.
In the shape of the more mature Banega, the still under-fire coach might just have found the key to allowing Messi's genius to light up the World Cup and take Argentina deep into the tournament.
