When Lionel Messi beat Bosnia-Herzegovina goalkeeper Asmir Begovic on Sunday (yesterday morning, Singapore time) to give Argentina a 2-1 win in their opening Group F match at the Maracana Stadium, it was also his second goal at a World Cup, breaking an eight-year duck.

That goal, his first since the 6-0 drubbing of Serbia & Montenegro in Germany in 2006, would have lifted a huge mental burden off the 26-year-old’s shoulders, which can only be a good thing in Argentina’s quest for a third World Cup, and first since 1986.

But that probably would not have happened had Argentina coach Alejandro Sabella not made a decisive tactical switch at half-time to inject life into a sluggish first-half performance in which they led through an own goal from Sead Kolasinovic.

Sabella brought on midfielder Fernando Gago and forward Gonzalo Higuain in place of centre-back Hugo Campagnaro and midfielder Maxi Rodriguez, respectively, a move that instantly opened things up for Messi. Argentina looked a different animal.

With Higuain partnering Sergio Aguero upfront, Messi flourished in the No 10 playmaker’s role, protected by midfielders Javier Mascherano and Gago, with attacking full-backs Marcos Rojo and Pablo Zabaleta supporting on the flanks.

That Argentina’s hopes of lifting the World Cup rests heavily on Messi is obvious. The onus is now on Sabella, long criticised for being a tactical tinkerman, to quickly settle on a formation that optimises Messi’s abilites, much like how Argentina’s 1986 World Cup-winning manager Carlos Bilardo built his side around Diego Maradona.

In 1986, Bilardo used three centre-backs in Jose Luis Brown, Jose Ciuciffo and Oscar Ruggeri who seldom ventured forward. In midfield, he used Sergio Batista and Hector Enrique as cover, Julio Olarticoechea and Ricardo Giusti on either flank, Jorge Burruchaga as Maradona’s running mate in midfield, and Jorge Valdano the lone forward. That allowed Maradona the freedom to do whatever he wished, without worrying about dropping deep to find the ball. That is what Messi needs.

On the surface, Messi’s post-match comments may not seem to say much. But decode it, and he might be sending a huge signal to Sabella.

“The first half was very difficult. I was alone and Kun (Aguero) was alone just like I was,” Messi was quoted as saying by the Associated Press.

Nicknamed “The Flea”, Messi is finally feeling at home with his national side after years of feeling unloved by his compatriots, who label him “The Catalan” — they see him as a product of Barcelona rather than Argentina’s domestic leagues.

In the first-half against Bosnia, Messi did not see enough of the ball, a scenario that happened in 2010 when the flamboyant attacking policy of then-Argentina coach Maradona meant he had to drop deeper and deeper to get the ball, severely limiting his effectiveness. But that changed with the introduction of Gago, who performs the Xavi and Iniesta role in supplying Messi the ball.

There were suggestions Sabella could return to his roots — as a former player with Estudiantes, as was Bilardo, he is schooled in defensive football — and adopt a conservative 5-3-2. But now, Sabella might be forced to re-consider, especially after switching to a more open 4-3-3 turned the match in their favour, which appears to be the prevailing sentiment in Argentina, including from influential La Nacion journalist Juan Pablo Varsky, who believes 5-3-2 is no longer enough.

Yet with Sabella you never quite know how he will line up his next side. He now has to decide whether to stick with Mascherano and Gago as the base of a midfield triangle with Messi at the apex and another forward in Higuain or Aguero, or revert to his defensive instincts.

Their match against Iran on Saturday could offer Sabella an opportunity to fine-tune his tactical formation and decide whether he should stay true to his defensive instincts, or adopt a more adventurous approach which Messi seems to favour.

It is a decision that could help decide if Argentina will return to the Maracana on July 13 for a possible meeting with Brazil in the final.