Hadden said his side would improve as the World Cup progresses

"It wasn't a tremendous performance but it was our first game and we wanted to start with a win," he told BBC Sport.

"Tremendous credit to the Portuguese, it was obviously a cup final for them. They never gave up and were incredibly tenacious throughout.

"We certainly expect to get better for the next game."

Hadden praised Dan Parks, who scored 15 points against the Portuguese, adding: "He got the game started for us in fine style.

"He's a quality stand-off and Chris Paterson, when he came on, showed he's no slouch in that position either.

"In the first game of the tournament there is a range of performances and as far as that's concerned it was okay.

"We certainly expect to get better for the next one and hopefully continue to make progress in this tournament."

Hadden said the Scots had every reason to feel confident about the rest of their games.

"We've prepared extremely well, have got the first hurdle out of the way - 'bring it on'."