Barcelona midfielder Javier Mascherano says they cannot relax after victory over Bayern Munich in the first-leg of their Champions League semi.

Lionel Messi shone as he notched a silky double and the Argentinian set up Neymar for a third late on as Barca triumphed 3-0 over Bayern Munich at the Nou Camp in the first leg of their semi-final.

"We have Messi so it's an advantage for us," Mascherano told Sky Sports 1. "I think it was a very tight game. Difficult, but we have the biggest chances to score. I think we played the game that we wanted to play before the game so we are really happy.

"Now we know how difficult it will be in Germany. It's a good advantage but it is not done. It's not done. Now we have to go in with the same mentality that we have today and try to do our job."

Mascherano was almost lost for words when asked about fellow Argentinian Messi, who pulled the strings to fashion Barca's huge win.

"He's a player that is impossible to describe him," he said. "It's just, you have to watch him. So we are happy, we are happy because it's a good result but we need to think about the next week and try to do our job to be in the final."