Gros Islet, St. Lucia: India are now one step away from a rare One-day International series victory in the Caribbean.

They face West Indies in the fourth and final ODI on Sunday at the Beausejour Cricket Ground confident in the knowledge that they cannot lose the brief series.

The visitors won the rain-affected third ODI by six wickets on Friday at the same venue to take an unstoppable 2-1 lead in the series.

India had won the high-scoring opening ODI by 20 runs last Friday at Sabina Park in Jamaica, and two days later, West Indies rebounded to secure an eight-wicket victory in a low-scoring second ODI at the same venue.

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India captain Mahendra Singh Dhoni praised the overall effort in his side for prevailing in the match, despite having to battle the weather and the Duckworth-Lewis Method which calculates targets in weather-affected matches.

"It was getting tight, and from our experience in Twenty20 cricket, we never felt under any pressure, although we required 11 from the last six balls," said Dhoni.

"Our final target (of 159 runs from 22 overs) was always achievable, once we had two specialist batsmen at the crease, and others like Harbhajan Singh to come, but it was hard to cope with the pressure," he added.

India's top-order batting had misfired in the second ODI which led to their huge defeat, but they got a meaningful start on Friday from Dinesh Karthik and Gautam Gambhir which set things up for the final charge.

Karthik made 47 from 43 balls, and Gambhir collected 44 from 38 balls, as they shared 95 for the first wicket, and Dhoni felt this was crucial to India's victory, and hopes to see more of this on Sunday.

"We are a side which really relies on our opening batsman to give us the momentum," said Dhoni.

"Once we get a good start, we really have the firepower to capitalise on it, and get a big total on the board."

West Indies, on the other hand, have to finish the series with a win which would ensure the series ends in a tie.

"We are very disappointed about the way we lost the third ODI," said West Indies captain Chris Gayle.

"At the same time, we have to pick ourselves up and get ourselves ready for the final game on Sunday. But we'll just have to take the positives that we can out of this game."

Gayle agreed that his side found it difficult to get the momentum in between the rain to set India a more formidable challenge, but he felt the final target was decent.

"We thought we had a chance of defending the target because it's a big outfield," said Gayle.

"But their openers gave them a good start. . .and they were running hard between the wickets, and putting a lot of pressure on our fielders as well, so we will have to work on this, and see if we can squeeze their batsmen a bit more in the outfield."

In bilateral ODI series, India have only once overcome West Indies on five previous trips to the Caribbean, and this was 2-1 in a three-match contest seven years ago.