Branislav Ivanovic has warned Serbia they have achieved nothing yet despite their famous World Cup win over Germany.
The Serbian's 1-0 victory over Germany on Friday has given the country a chance of reaching the knock-out phase of the World Cup.
Serbia next face strugglers Australia, who were beaten 4-0 by the Germans, aware a victory could be enough to take them through.
But Ivanovic is taking nothing for granted against the Australians, although he admits morale is improved after they lost their opening fixture against Ghana.
The Chelsea stopper said: "It's given us back the respect that we lost in the first game.
"But we have not finished. We must perform, we must stay compact, we must stay strong in our third game. We now must start thinking of the third game against Australia.
"In this game, we showed character and we will just try to do our best on the pitch.
"Everyone is happy now at the moment and there's a great feeling - but we are not qualified. We just have three points and we need to keep the same focus for the third game.
"We have to show how we played today again against Australia and try to do our best, because it's a very difficult game.
"When you have to win, you have to be strong, you have to show the quality, and show the football to be in the next round."