Argentina coach Alejandro Sabella urged his players to raise their game after seeing them labour to overcome Bosnia-Hercegovina 2-1 in their opening World Cup match in Rio de Janeiro.

“If we analyse the two halves, I’d give us six out of 10,” Sabella told a press conference after Sunday’s Group F encounter at the Maracana. “We have to improve. Part of this improvement is my responsibility.”

After seeing his side toil in a 5-3-2 formation in the first half, Sabella reverted to a 4-3-3 system at half-time and sent on Gonzalo Higuain and Fernando Gago.

The changes took Argentina back to the set-up they had used in qualifying and they proved effective, with Messi thriving amid the extra space and scoring following a one-two with Higuain.

“In the first half, we controlled Bosnia well, but we weren’t getting in behind. That’s what we managed to do in the second half,” Sabella said.

“We got in behind more after Higuain and Gago came on and with (Angel) Di Maria dropping deep. We were able to play our game, the one we’d played during the qualifiers.

“We played differently than usual in the first half, but it was my decision. In football, you need a balance between defence and attack.

“We had to give a bit more power to the attack in the second half. The best whatever happens.”

Messi in particular seemed to appreciate the switch and his goal carried all of his hallmarks -- a sudden burst of acceleration, a neat one-two, a sidestep that flummoxed two defenders, and an unerring low strike. 

“Messi is the best player in the world and he doesn’t need much, but there’s always a context that can aid him a bit more,” added Sabella.

“Giving him more passes and then giving him better support makes him stronger.”

Messi’s strike ended his eight-year wait for a second World Cup goal after he failed to find the net once at the 2010 tournament in South Africa, when Argentina were crushed by Germany in the quarterfinals.

While he has yet to bend a major tournament to his will, Sabella does not believe that he needs to win the World Cup to be considered the world’s best player. “Messi is the best player in the world whatever happens at the World Cup and one of the best players of all time whatever he does at the World Cup,” he said.