Branislav Ivanovic has warned Serbia they have achieved nothing yet despite their stunning World Cup win over Germany.

The 26-year-old Chelsea defender played his part in yesterday's famous 1-0 victory over Joachim Low's men in Port Elizabeth as the Serbs rekindled their hopes of making it to the last 16.

A 1-0 defeat by Ghana in their opening Group D game had left them facing an uphill task, but they responded superbly as 10-man Germany floundered in the wake of Miroslav Klose's first-half dismissal.

However, Ivanovic knows their heroics at the Nelson Mandela Bay Stadium will count for little if they do not turn in a similar performance against Australia in Nelspruit on Wednesday.

Ivanovic 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."

Ivanovic was in the thick of the action as Germany self-destructed, and it was he who was fouled by Klose for the striker's and the game's first booking with 12 minutes gone.

Twenty-four minutes later, Spanish referee Alberto Undiano produced a sixth yellow card and Klose's second for a trip on Dejan Stankovic, and the game's pivotal moment had arrived.

Serbia scored what proved to be the match-winning goal within two minutes when striker Milan Jovanovic controlled Nikola Zigic's knock-down from a Milos Krasic cross and fired home from point-blank range.

However, they had keeper Vladimir Stojkovic to thank when he saved a 60th-minute Lukas Podolski penalty after Nemanja Vidic had inexplicably handled inside the box.

The Manchester United defender was a relieved man, but his thoughts too quickly turned to the clash with the Socceroos.

Vidic said: "I have played against a few of their players in England - Lucas Neill, Tim Cahill, Brett Emerton - they have three or four players in England and I have a big respect for their team.

"Physically, it will be a difficult game.

"Our people will be satisfied after we won this game, and that's the most important thing.

"If we get to the second round, they will be very, very happy."

For the Germans, who cruised past Australia in their opening game, defeat came as a wake-up call and one which is unlikely to go unheeded.

Defender Per Mertesacker said: "We must approach the game against Ghana as a cup final. It is an absolute must-win game for us."

Low was philosophical in defeat, but leapt to the defence of youngsters Holger Badstuber and Thomas Mueller, who performed so well against Australia, when asked if it had been a game too far for them.

He said: "I don't think they were over-taxed, I don't think it was too tall an order for them.

"Badstuber didn't defend particularly well for the goal, but Krasic is a great international player and you can't always counter such attacks.

"Serbia played extremely well and deserved that goal."