South Africa face the United States in London on Wednesday looking to secure their place in the World Cup quarter-finals despite upsets suffered so far.

The Springboks are determined not to let their guard down after losing 34-32 to Japan in their opening match and then seeing captain Jean de Villiers forced out of the tournament through injury.

They have recovered with wins over Samoa and Scotland but still need to beat the United States to be sure of a last-eight place.

"You have to assess as you go," said flanker Francois Louw ahead of the Pool B match at London's Olympic Stadium.

"The tournament didn't start as well for us as we hoped. Obviously after Japan we had to regroup and pull together and move forward from that. So far we're on track with that."

"There's another big game ahead of us in the sense that it's our final chance, we have to come out victorious in this game for us to progress. There is no other option."

Fourie du Preez has taken over as captain from de Villiers, who quit international rugby after suffering a fractured jaw against Samoa.

"It's a week and a half, and so far I've quite enjoyed it," du Preez said.

"I don't enjoy media conferences, I don't enjoy big speeches, but when I get on the field I love it," he added.

"I think it's just having an influence on the guys around you. Not having to say too much. I've got great guys around me, guys like Schalk Burger. It is just an absolute pleasure working with those guys."

South Africa assistant coach Johann van Graan said the United States have made an impact even though the Eagles have lost their opening pool matches against Samoa and Scotland.

"I've actually been quite impressed by their defence. They are one of the teams in the competition at the rush (defence), maybe the fastest," he said.

"That does pose different challenges. If you look at what they have done in the World Cup they've defended quite well."

South Africa's matchday 23 includes the experienced Morne Steyn, who has dropped behind rival fly-halves Handre Pollard and Pat Lambie when it comes to the favoured No 10 of coach Heyneke Meyer, and uncapped scrum-half Rudy Page.

"I've been with Morne for a lot of years," said van Graan. "The one thing I can say about him is he always stays the same whether he's in the team, on the bench or holding bags, his attitude is absolutely fantastic and he can't wait to go."

"And then Rudy Page, he's really worked hard. And what a great mentor in a guy like Fourie (du Preez) he can learn from. He's going to take this opportunity and make the most of it."

Meanwhile van Graan said the importance of Wednesday's had helped clarify minds.

"I think a week in rugby is a very long time," he explained.

"For us it's another Test match and every Test match is a must-win for us. After the first round it was pretty simple: we've got to win every single game to get into the quarter-final.

"The Americans have played some decent rugby in this tournament, there are no weak teams in this competition, Anybody can have an upset and that's just the way it is."
Source: AFP