India's number one ranking in Test cricket is on the line when they take on South Africa in the second and final Test at the Eden Gardens, beginning on Sunday.

Mahendra Singh Dhoni's side went into the series in number one position, leading Graeme Smith's side by four ratings points. But after having lost the first Test at Nagpur by an innings and six runs, the host are in danger of losing the top spot.

India must win the second Test to draw the series and retain the number-one position it snatched from South Africa on December 6 after defeating Sri Lanka 2-0.

If South Africa beats India 1-0, it will go to 123 ratings points and India will drop to 122 ratings points, while in case of a 2-0 win, the Proteas will rise to 125 ratings points and India will drop to 120 ratings points.

India's batting suffered in Nagpur in the absence of the experienced Rahul Dravid, Vangipurappu Laxman and Yuvraj Singh due to injuries, despite Virender Sehwag and Sachin Tendulkar scoring centuries.

Number three batsman Dravid (jaw injury) and Yuvraj (wrist) are ruled out of the entire series, but Laxman, who missed the first Test because of a finger injury, was declared fit on Thursday.

He has happy memories of the Eden, having hit a historic 281 as India beat Australa in the second Test in 2000-01 after following-on. His return should bolster the middle-order.

India will have to come up with solid batting against the South African pace battery. Can they weather another Dale storm? The pacer took a match haul of 10-108 in Nagpur after Hashim Alma scored 253 not out and Jacques Kallis hit 173 to guide the tourists to an imposing first innings total of 558-6 declared.

The hosts have included one-day specialist Suresh Raina and made two other changes to the squad for the Test in a move to strengthen their batting. Dinesh Karthik and S Sreesanth have also been included in the squad at the expense of Wriddhiman Saha, Abhimanyu Mithun and Sudeep Tyagi.

Karthik's return is expected to boost the batting. He was inexplicably dropped after the tour to Bangladesh, and considering his recent good show in the Duleep Trophy final for South Zone, where he scored a hundred in each innings, he should make the final eleven.

South Africa are high in confidence after the emphatic victory in the first Test  Interestingly, they faced a similar scenario in 2008, when they crushed the Indians in the first Test at Ahmedabad, but were undone on a turning track in Kanpur and the series ended 1-1.

Right-hand batsman A B De Villiers said the team is well-prepared for any eventualities this time, having learnt from previous failures.

"We are not very worried about the pitch. Like I said, we are going to just focus on our game plans, and playing good cricket. How the pitch is going to play we don't know; the way the Indians are going to play we are not sure. We are just going to go out there and focus on our game plans to win 2-0," he said.

South Africa captain Graeme Smith's participation in the Test is in doubt after he injured his finger during training on Friday.

The laft-hander was undergoing catching practice in the morning when he hurt his little finger on the left hand. He was immediately rushed to a local hospital.

An MRI scan confirmed ligament damage and there is considerable swelling around the injury.

South Africa's medical team expressed confidence that the swelling will subside in the next 24 hours and Smith will put his finger to the test during Saturday's practice, after which a decision on his fitness will be taken.

South Africa expect the pitch at Kolkata's Eden Gardens to assist spin, India's traditional strength. Media reports suggested that the Cricket Association of Bengal curator, Prabir Mukherjee, got a call from a top Board of Control for Cricket in India official, instructing him to prepare a turning track for the Test.