In March they looked like they risked failing to qualify for the World Cup for the first time since 1970.
He is thrilled to have 29-year-old Barcelona forward Messi on his team having faced him in the 2015 Copa America final when his Chile side upset Argentina on penalties.
Argentina face four further World Cup qualifying games, starting with a stern test away to Uruguay in August.
Argentina now lie fifth in their qualification group and only the top four automatically go through to the finals.
He subsequently succeeded Unai Emery in Andalucia, taking Sevilla to fourth place in his first and only season at the club as well as a last-16 appearance in the Champions League.
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The two leaders also found common ground on terrorism, following the attack on a pop concert in Manchester that killed 22 people. Among the agenda items the Italian presidency has had to capitulate on is a substantial reference to tackling climate change.
Argentina had been without a manager since they dismissed Edgardo Bauza on April 10 while holding the job for just eight months. "Let's hope we can generate something important for Argentinian football", said Sampaoli, who left for Australia with his squad for the start of a two-match friendly tour yesterday.
But Sampaoli believes in their chances of reaching Russian Federation 2018, saying: "We are convinced that we have the resources to qualify".
"I spoke with Leo and we're both excited", Sampaoli was quoted as saying by BBC.
"We want the most genuine and pleasant version of the best player in the world, we want him happy here", Sampaoli said, adding that he'd spoken with Messi in recent days.
Another change Sampaoli plans involves Javier Mascherano, who has featured in midfield for the national team despite playing as a defender for Barcelona.