Angola coach Luis Oliveira Goncalves has warned his side that they must take their chances if they are to have any hope of progressing past the group stages.

The World Cup debutants face Iran, Mexico and Portugal in Group D, with Goncalves worried that his players are not clinical enough in front of goal.

He said: "The players go upfield and then don't score goals.

"We don't have the capacity to score a lot of goals against these teams so when we have an opportunity, we have to know how to grab it.

"When I speak about concentration, I don't just mean it for the defenders. It also counts when the players are on the offensive. The team as a whole needs to defend better.

"The team is evolving from game to game. On Monday, for example, we played with ten players for 54 minutes and our team managed to put the pressure on the United States.

"We made a few mistakes but we are going to work on the strategy of the game, mainly for the team to defend better and on our counter-attack."