Scotland's limp defeat to Ireland in their World Cup opener prompted questions about the squad's heart and desire but head coach Gregor Townsend said his players had proved their mettle in their bonus-point win over Samoa.

Japan's stunning win over Ireland on Saturday had left Scotland with an uphill task to qualify for the quarter-finals but they cleared the first hurdle with the 34-0 win over the Samoans, the first time the Pacific islanders had been blanked in 30 World Cup matches.

First-half tries from Sean Maitland and Greg Laidlaw set them on their way but Scotland had to dig deep after the break, their pressure finally paying off as referee Pascal Gauzere awarded them two penalty tries.

Townsend, himself the target of heavy criticism after the Ireland defeat, was proud that the real Scotland had stood up.

"That was a true reflection of who we are and what we're capable of, and what playing for Scotland means for these players," he told a news conference.

"That was a tough challenge. They had to rise up and face knowing that if they underperformed tonight we were out of the World Cup.

"I take responsibility for not preparing the team well enough to start against Ireland but that doesn't make us a bad team. Tonight was great to see them get the reward for that effort."

Scotland have been guilty of leaking early tries throughout the year and Townsend was particularly pleased to keep Samoa off the board.

The Samoans put Scotland under real pressure at the end and looked set to claim a late try but were stopped just short of the line by a desperate Scottish defence.

"That's a real credit to the players and also to our defence coach Matt Taylor," he said.

"Tonight they defended with real passion, to get off the line and put big hits on some very big men and to do it time and time again knocked the confidence of the Samoan guys."

Scotland had been talking up the importance of securing a win over the Samoans first and foremost, then chasing a bonus point if the situation presented itself.

Stuart Hogg's howitzer of a drop goal from 40 metres out just before halftime put the Scots 20-0 up, making the game safe and setting the stage for the bonus-point pursuit.

"We didn't chase anything too early, we knew how tough a game it was," said skipper Stuart McInally.

"It was 3-0 for a long time in that game, we just had to keep playing the way we wanted to. We were confident we'd get our tries later in the game."