A Thomas Muller hat-trick has given Germany a comfortable 4-0 victory over 10-man Portugal in their opening match of the World Cup.

Portugal had the first opening of the match on seven minutes following a frantic start, but Cristiano Ronaldo's effort from a tight angle was kept out by Manuel Neuer.

Germany nearly scored at the other end just a minute later after Rui Patricio's scuffed clearance went straight to Sami Khedira, though the midfielder could only fire off target from distance.

The Germans eventually made the breakthrough with 11 minutes on the clock as Joao Pereira brought down Mario Gotze inside the box, allowing Muller to sweep his penalty past Patricio.

Both teams showed plenty of attacking intent for the remainder of the half, and Portugal nearly grabbed an equaliser on 26 minutes when Nani shot narrowly over from the edge of the area.

Despite an even opening, Germany took control of the contest with 31 minutes played thanks to Mats Hummels's powerful header from a corner.

Portugal's evening got worse on 36 minutes when Pepe was shown a straight red card after a confrontation with Muller.

The defender took exception to what he believed was an over-reaction from the forward following an earlier clash, but the referee had no option other than to send him off after he went into his opponent with his head.

Germany took advantage of the extra man by extending their lead further on the stroke of half time as Muller was picked out by Gotze before supplying a ruthless finish from inside the box.

While the first half was full of action, there was a more subdued pace to the second period as Germany looked to conserve their energy.

The three-time champions could have made it 4-0 when Mesut Ozil was denied by Patricio from close range before Muller headed the rebound over the crossbar as Portugal struggled to make an impact.

Portugal rarely threatened their opponents, and Germany almost found the net again with 20 minutes left to play, but Gotze wasted a decent opening by shooting over from 12 yards.

Despite Germany's dominance, the Portuguese managed to carve open a chance soon after when Nani's stinging drive was palmed away by Neuer.

However, Germany had the final say as Muller pounced from close range to complete his hat-trick with just over 10 minutes remaining.