Portugal captain Cristiano Ronaldo has backed his side to overcome Spain in their blockbuster World Cup Round of 16 clash.

The Portuguese are set to take on Spain in what is expected to be a mouth-watering encounter at the AT&T Stadium in Arlington.

Roberto Martínez’s side made their way to the last 16 after they secured a hard-fought 2-1 victory over Croatia in the Round of 32.

The veteran forward hailed Spain as perennial contenders for major honours but believes the match will be decided by the finest of margins—and is convinced Portugal will come out on top.

“As you know very well, I have a very special affection for Spain. My family is almost Spanish,” Ronaldo told FIFA.

“Spain are always candidates to win any tournament, whether it’s the World Cup, the European Championship, or any other competition.

“In the end, whoever manages to take advantage of the small details in the match will be the winner.

“And I hope that team will be Portugal. That’s my feeling, and I believe we will win.”