Chile star Arturo Vidal gave his team a timely boost just two days before their opening World Cup clash against Australia as he took part in training.

The 28-year-old has been struggling with inflammation in his knee following an operation on his meniscus just over a month ago.

But the Juventus midfielder trained with his team-mates on Wednesday, the first time he has been able to do so since making a surprise 15-minute cameo comeback a week ago in the 2-0 friendly victory over Northern Ireland.

Vidal joined the squad a few minutes after they had come out to train at their Toca Da Raposa II base in Belo Horizonte, and showed no signs of discomfort.

He is a vital cog in coach Jorge Sampaoli’s team and his presence will be imperative in their next two games against Spain and the Netherlands if they want to progress to the knock-out stages.

Despite being drawn in such a tough group, forward Alexis Sanchez is feeling confident about their chances, although he acknowledges it will be hard to finish above reigning champions Spain in Group B.

“I believe Chile will win the World Cup, if I didn’t believe that I would be sitting at home in front of the television,” he said. “I would be happy if we finished second behind them (Spain).”

Australia goalkeeper Mat Ryan, meanwhile, revealed his side could not wait to get stuck into Chile.

Last Friday saw the Socceroos make fellow qualifiers Croatia, Brazil’s opening day rivals, work hard for a single goal win in their final warm-up and Ryan, 22, said nobody could doubt Australia’s will to succeed.

“I just can’t wait for Friday to start – just let the excitement take over. Everyone’s fairly relaxed at the moment. But I dare say that’s about to change in the coming days,” said Ryan.

LIKELY LINE-UPS

Chile (3-5-2)
Bravo; Jara, Medel, Mena; Isla, Diaz, Vidal, Aranguiz, Beausejour; Vargas, Sanchez

Australia (4-5-1)
Ryan; Franjic, McGowan, Spiranovic, Davidson; Leckie, Milligan, Jedinak, Holland, Oar; Cahill

PLAYERS TO WATCH

Chile – Arturo Vidal
Expected to recover in time from the knee injury that made him a doubt, Juventus midfielder Arturo Vidal will be central to making this exciting Chile side tick. Regarded as one of the best central midfielders in the world, Vidal has the talent to drive his nation into the latter stages of the tournament.

Australia – Mile Jedinak
The Socceroos will be up against it in Brazil and a key part of any potential success they have this summer will be reliant on their ability to shut out the opposition. Up against Vidal, Australia's combative captain, Jedinak, will need to be at his very best in recycling possession in the centre of the park.

PREDICTION

This Australia side is incredibly inexperienced and lacks players plying their trade at the highest level. In comparison, Chile are an energetic, attacking outfit that can make a real impact at this year's World Cup. Expect this match to show a huge gulf in class between the two teams. Chile 4-0 Australia