Germany's goal-scoring legend Gerd Mueller is backing compatriot and namesake Thomas Mueller to eventually claim the record for the most World Cup goals.

The 24-year-old Thomas Mueller scored the first hat-trick of Brazil 2014 in Germany's 4-0 rout of Portugal on Monday to leave him with eight goals at World Cup finals.

Gerd Mueller, 68, nicknamed 'Das Bomber', retired after scoring the winner in the 1974 World Cup final to leave him with 68 goals in 62 appearances for West Germany.

His previous record of 14 World Cup goals, later matched by current German squad member Miroslav Klose, was only broken when Brazil striker Ronaldo claimed his 15th at Germany in 2006.

"I am certain that Thomas Mueller will eventually get the World Cup goal record, as he still has two or three more World Cups in him," Mueller senior told Wednesday's edition of Sport Bild.

Thomas Mueller is already on course to retain the Golden Boot he won four years ago, after finishing joint top-scorer, having also won the best young player awards in South Africa.

If he wins the Golden Boot, he would become the first player to retain the award and the first time a single country has won the Golden Boot three times in succession after Klose claimed the award in 2006.

"I hope he retains the Golden Boot and I'll keep my fingers crossed for him," added Gerd Mueller.