Fears that Djibril Cisse might miss the World Cup with a broken leg spoiled France's 3-1 warm-up win over China in Paris last night.

The striker was hurt in a clash with a Chinese defender 10 minutes into his team's last match before they fly out to Germany today.

Cisse was taken away on a stretcher and received treatment on his right leg for several minutes before going to hospital. "We're really worried," coach Raymond Domenech told French television at halftime.

"It's a drama. At the moment, we don't know the exact nature of the injury." The Liverpool forward had been expected to start France's opening World Cup game against Switzerland in Stuttgart on Tuesday.

Germany captain Michael Ballack is in danger of missing the curtain-raiser against Costa Rica tomorrow after failing to complete a training session 48 hours before the game.

Ballack has been struggling to get over a strain to his right calf. He finally returned to training last night but the German FA said the muscle was not strong enough for him to continue.

Ballack famously missed the final match of the last World Cup through suspension and he now seems increasingly likely to miss the opening match of this one.

The absence of the 29-year-old would be keenly felt by Jürgen Klinsmann's relatively young team.

Brazil star Ronaldinho (26) has asked referees to protect him and his team-mates.

The Barcelona superstar believes Brazil's opponents will attempt to stop them from playing their attractive football.

"All the teams are waiting for us and will be doubly alert in paying attention to our attack," said the world player of the year. "It's vital the refereeing is rigorous because of our style of playing.

"Every team we play regardless of their normal style of play defend against us," he added. "It is difficult to score goals in that case. The others play tight at the back and will wait to hit us on the counter-attack."