It is needless to be said that a team that has taken an initial lead in the test series be it anywhere on earth will definitely have the momentum and the pressure would obviously be on the opposition. This is more so in the case where the series is a two match affair and a win in the first test would guarantee the opposition atleast a level in the series in case they lose the 2nd test. This is what the Proteas enjoy at the moment, with South Africa taking an unbeatable lead in the series , a loss in the 2nd test would only see them level the series and a draw would ensure a series win for the Proteas.
However, some positives that South Africa enjoyed in the first test that was played at Nagpur, which might not be the case at Kolkata should also have been taken by A B de Villiers before making any such comment. India were without a second wall (after Rahul Dravid) in V V S Laxman who is termed to be fit for the second test at Kolkata starting day after on Sunday. The second point is that the Kolkata pitch is hinted to be a turning track, playing on which can be a nightmare for the batsmen from South Africa, which will surely haunt them this time as well.
Though there is hardly any noted spinner in the Indian squad for the exception of Harbhajan Singh, Harbhajan Singh is alone enough to put pressure upon the South African batsmen. Moreover, there is Zaheer Khan, who can bring fresh nightmares for atleast Graeme Smith if not for anything else for, Zaheer Khan has been seen getting Smith out in the past 5 tests and 8 innings that were played. The most recent one where Smith was taken by Zaheer being in the Nagpur test. It was the same venue where South Africa lost to India where Harbhajan Singh took 7 wickets in the 2nd innings and 2 in the first.
In that match in 2004, spinners took 13 out of the 20 South African wickets, with all 10 wickets in the 2nd South African innings going to the spinners Anil Kumble and Harbhajan. In 2008, South Africa succumbed to India's bowling in the 3rd test at Kanpur, with needless to be said spinners made the most of the South African batsmen's weakness. It was after South Africa won the 2nd test at Ahmedabad that they lost the 3rd test at Kanpur by 8 wickets. Moreover, the Kanpur test lasted for just 3 days, with the South African 2nd innings lasting just 55.5 overs and 121 runs long. Now, one can guess the momentum that A B de Villiers thinks his team to be enjoying!