Gonzalo Higuain refused to be drawn on questions about his future following more rumours linking him with a move to Barcelona.
The former Real Madrid striker enjoyed an excellent first season with Napoli, scoring 22 goals in 41 games in all competitions, and reports have emerged that Barca are interested in buying him this summer.
|WORLD CUP SOCIAL HUB
|Keep up with all the latest news from Brazil and get involved in the debate on Twitter with our new World Cup Social Hub|
"I know nothing [about Barcelona's interest]," he told reporters. "When I'm with Argentina I'm only thinking about this team.
"We all know what Leo does for us and can win a match at any moment. He is a key player for our team."
The striker then touched on the Albiceleste's World Cup chances, saying they are hopeful of going on to win the tournament outright, but admitted second round opponents Switzerland will be a difficult test.
"We feel there is a country behind this dream and hopefully we can give joy to the people with this cup," he added.
"I have three Swiss colleagues [Valon Behrami, Gokhan Inler, Blerim Dzemaili at Napoli] and we must play well. We know their strengths and weaknesses.
"It's a World Cup that has had a lot of surprises and so we must be cautious. We must respect Switzerland so we don't get taken by surprise."