South American XV 21 England 41: It is ‘crystal clear’ to Lancaster what lies in store for England

South America XV Tomas de la Vega, right, jumps for the ball with England's Matt Kvesic

Billy Vunipola scored a six-minute hat-trick, Ben Foden touched down twice and there were tries from Tom Wood and Paul Doran-Jones as England rallied from an error-strewn start.

England conceded a penalty try after 17 minutes and had Jonny May sent to the sin-bin – but that setback shocked Lancaster’s men into action and they scored 31 points in 21 minutes.

But the CONSUR XV kept coming at England and they dominated the final quarter as well, during which time Alex Corbisiero was sin-binned for conceding successive scrum penalties.

England face Argentina in the first of two Tests in Salta next Saturday and Lancaster said: “In terms of preparation it has been ideal.

“They were difficult opposition and we struggled in the first quarter and the last quarter to get the continuity we wanted.

“We were pleased to be 31-7 ahead at half-time after a slow start.

“In the second half our set-piece ball dried up a bit.

“The most important thing for me (from this game) is that it is now crystal clear exactly how difficult it will be next Saturday.”

Vuniopola’s hat-trick on his first senior England start capped a memorable weekend for the family, coming the day after his elder brother, Mako, had made his debut for the British and Irish Lions.

But with Ben Morgan set to start at No 8 and England acutely aware of the physical battle that lies ahead, particularly at the breakdown, Vunipola is not even guaranteed a place in the squad to face Argentina.

“He had a good game in terms of try-scoring,” Lancaster said.

“I need to look at his contribution and those of all the others in back row because there are lots of decision to be made.

“The breakdown was fiercely contested and at times we didn’t deliver as good ball as we had wanted.

“I have some decisions to make as to how we go about the game.”

Lancaster must also decide whether to start with Tom Johnson or Matt Kvesic at openside flanker and England once again fell foul of refereeing interpretations in the scrum.

Henry Thomas was penalised twice in quick succession in the first half and Corbisiero sin-binned in the second, much to his surprise.

“We have to be better at managing the interpretations of the referee,” said Lancaster.

“We want a good scrum and clean ball.

“It is up to us to adapt.”

Samoa began their tour of South Africa in forgettable fashion as they crashed to a 74-14 defeat against the Golden Lions at Ellis Park in Johannesburg.

Scotland open their summer tour against Samoa in Durban next weekend.