Five key players in World Cup Group G:

Philipp Lahm - Germany

Born: 11/11/1983, Caps 106

Injury to Michael Ballack thrust the Germany captaincy on Lahm before the last World Cup and the right-back has barely looked back since taking over the arm-band.

An ankle knock during the German Cup final for Bayern Munich hampered Lahm's preparations for Brazil, but the 30-year-old will lead 'die Mannschaft' out for their opener against Portugal.

Lahm has shown his flexibility this season after being switched from right-back to defensive midfield for Bayern, an experiment Germany coach Joachim Loew has copied.

With five goals to his credit, Lahm has a knack of scoring key strikes for Germany, claiming the first goal at the 2006 World Cup and putting them into the Euro 2008 final with a 90th-minute winner against Turkey.

Cristiano Ronaldo - Portugal

Born: 05/02/1985, Caps 110

The 2013 Ballon d'Or winner needs little introduction but he faces a race to be fit for the World Cup.

Having picked up hamstring and knee injuries for Champions League winners Real Madrid, the first challenge for Ronaldo is to be fit for these finals.

His stunning hat-trick against Sweden in last November's play-off booked Paulo Bento's side their Brazil berth as he scored all four goals in the two-legged play-off.

He netted twice in Portugal's 5-1 friendly win over Cameroon to take his tally to 49 goals, becoming his country's all-time leading goalscorer.

He has a golden chance to get Portugal's campaign off to a flying start in the opening match against Germany in Salvador, which could be a key factor in deciding the group.

Jermaine Jones - USA

Born 03/11/1981, Caps 43

The 32-year-old Frankfurt-born defensive midfielder turned his back on Germany after winning the last of his three caps in friendlies for 'Die Mannschaft' in 2008.

He has already made more than 40 appearances for the USA since 2010 and scored two goals.

The Besiktas star could return to haunt his old side when Jurgen Klinsmann's Stars and Stripes play Germany in Recife on June 26 in their final Group G clash.

Klinsmann turned to Jones, a powerful box-to-box midfielder who is strong on the tackle, to put some steel in the USA's midfield and he helped his country beat a weakened Germany side 4-3 win in a friendly in Washington in June 2013.

Kevin-Prince Boateng - Ghana

Born 6/3/1987 - 12 caps

Heavily tattooed and with a glamorous television presenter girlfriend, Berlin-Born Boateng is Schalke's rock'n'roll attacking midfielder.

Despite rising through Germany's junior ranks, he opted to play for Ghana, the country of his father, and helped the Black Stars reach the quarter-finals of the 2010 World Cup.

He is set to face his half-brother, Bayern Munich centre-back Jerome Boateng, when Ghana play Germany in Fortaleza on June 21.

Having made his debut as an 18-year-old at Hertha Berlin, Boateng won the 2011 Serie A title during three seasons with AC Milan.

He hit the headlines in January 2013 for walking off during Milan's friendly at Pro Patria because of racial abuse.

Miroslav Klose - Germany

Born 09/06/1978, Caps 132

Having turned 36 just before the World Cup kicks off, Poland-born Klose travels to Brazil as the only recognised striker in the Germany squad.

Having scored 14 goals at three World Cup finals, Klose, Germany's joint top-scorer, can break the original Brazilian Ronaldo's all-time record of 15 goals in Brazil.

His five goals at the 2006 World Cup won him the golden boot award having finished joint second four years earlier in Japan and South Korea.

His header against Armenia on Friday left Klose as Germany's all-time top-scorer with 69 goals in 132 appearances to break Gerd Mueller's record.