Defending champions India sealed their place in the World Cup knockout stages with a nervy run chase against West Indies in Perth.

Captain Mahendra Singh Dhoni helped to steer his team to a four-wicket victory in a low-scoring Pool B match.

India, who bowled the Windies out for 182, remain one of two unbeaten teams in the tournament after scrambling the verdict with 10.5 overs to spare on a typically bouncy pitch at the WACA.

Dhoni was therefore able afterwards to reflect, with a little relief, on an awkward mission completed.

“I think it was a difficult wicket, with variable bounce and extra bounce for the fast bowlers,” he said in an interview broadcast by Sky Sports World Cup.

West Indies won the toss on a glorious afternoon, but Dhoni sensed it was his team who ended up with the best of the conditions.

“I don’t think it misbehaved as much as it did in the first innings,” he added.

“Overall, I was very happy with the performance.

“Our lower middle order has not been tested before, so it was a good opportunity against a good bowling line-up.”

West Indies top order were hapless in the first 10 overs, and they might have been bowled out even more cheaply but for four dropped catches by India and captain Jason Holder’s second successive half-century from number nine.

Dwayne Smith struggled badly against India's new-ball pair, eventually edging behind off Mohammad Shami (three for 35).

Chris Gayle was out of sorts too, dropped twice and then holing out to a mispull off Shami — but not before a mix-up with Marlon Samuels saw the Windies number three run out for just two.

Captain Denesh Ramdin could not halt the slide, aiming an expansive cover-drive to a swinging low full-toss first ball and edging on to Umesh Yadav.

Lendl Simmons and Jonathan Carter almost doubled the score until the former fell pulling Mohit Sharma to deep backward-square.

Darren Sammy was dropped by Ravindra Jadeja on five, when he mistimed a skier into the off-side ring off Mohit.

Andre Russell was soon gone instead, hitting Jadeja's first ball straight to long-off.

But Sammy stayed long enough to help Holder (57) shepherd the Windies into powerplay, before he was caught behind off the returning Shami.

The captain struck four fours and three sixes from 64 balls but was last out, another hitting Jadeja to long-off, with almost six overs unused.

Two wickets in an impressive new-ball spell from Jerome Taylor gave the Windies renewed hope, both openers going as Shikhar Dhawan was caught at second slip and Rohit Sharma edged an attempted drive behind.

Virat Kohli threatened to shorten the chase until he hooked Russell into the hands of Samuels — and when Ajinkya Rahane went to a marginal DRS verdict, caught behind off Kemar Roach, India had lost four wickets with more than 100 runs still needed.

Suresh Raina struggled against the short ball before edging a cut behind off Smith's medium-pace, and the same tactic from Russell saw Jadeja pull Russell to a juggling Samuels.

But Dhoni engineered an unbroken half-century stand with Ravi Ashwin and finished top-scorer with 45 not out in a curious contest which contained 47 extras.

Holder knew where it had gone wrong for the Windies — with the bat.

“We just didn’t hang in long enough. We lost momentum and never really recovered,” he said.

“We didn’t apply ourselves well enough when we batted, and never caught up in the game.”