The Springboks not only let the British and Irish Lions slip in the back door, they literally "opened the front door" when the two teams met in the first Test of their three-match series in Durban at the weekend.

This is how star flank and world cup winner Juan Smit saw his team squandering 19-point lead (26-7) to sneak a 26-21 win over the Lions in the opening international.

While a lot of attention was focussed on the rash of replacements, which even coach Peter de Villiers admitted, may have been ill-times, Smith felt the team opened the door to let the Lions back in by changing their approach on defence.

And he promised that they will rectify the matter this week, and the tourists can expect a committed, 80-minute effort from the Boks on defence.

"Our defence wasn't as accurate as it was in the first half," Smith said of the last quarter, in which the Lions scored two late tries to narrow the gap to just five points.

"We didn't go fetch them on defence as we did in the first half," he added.

The 28-year-old Smith, a 55-Test veteran, said the Boks were concerned about the opening Test. But with that behind them, they can now focus on their strengths and weaknesses.

Asked what the biggest concerns will be when they starting their preparations ahead of the second Test in Pretoria this coming week, Smith pointed to defence as one of the key areas..

"We have two very contrasting halves," he said of the Durban encounter, adding: "In the first half our defence was spot on - we allowed them no space or time. The second half was exactly the opposite.

"That allowed them to get momentum, particularly out wide and in the midfield.

"That is something we are going to work on in training this week.

"One of our strengths is to physically dominate on defence and in the second half we didn't. But these are minor things we can correct this week ahead of the next Test [in Pretoria]."

The flank said the way they performed in the second half in Durban is "not what we wanted", but added that in Test rugby you take any win.

He felt that having won in Durban, despite the second-half slump, the team is in a good position to kick on.

"There is a calmness in the Bok team at the moment," Smith said, adding: "There are plenty of positives [from the Durban encounter].

"We know exactly what we have to work on this week. We realise that when you get such an advantage [26-7] you have to maintain that pressure - get that extra score that kills off the opposition.

"And exactly the opposite happened [in Durban]," he said.

365