Pakistan could not break their India jinx in the 50-overs World Cup on Saturday but more than their seven-wicket defeat by the arch-rivals, it was the manner in which they lost that is troubling the 1992 champions.

Hosts India, egged on by a 100,000-plus crowd at a heaving Narendra Modi Stadium, maintained their unbeaten record against Pakistan with a comprehensive victory, outperforming their rivals in all departments.

Pakistan, cruising at 155-2 in the 29th over, suffered a spectacular meltdown to be all out for 191 with more than seven overs left in their innings.

India then returned to lay bare Pakistan's bowling frailties and romped home with nearly 20 overs to spare in the lop-sided blockbuster.

Team director Mickey Arthur accepted Pakistan batters lacked aggression in their first loss in three matches.

"I just think we were a little bit timid tonight with our overall performance," Arthur told reporters after the match.

"To go from 155 for two, as it was, to 190-odd all out is just not on.

"Credit to India, I thought they bowled really well, but I just thought our performance was just a little bit timid."

Skipper Babar Azam (50) and in-form Mohammad Rizwan (49) forged the only half-century partnership in the Pakistan innings.

Arthur called them "classy performers" but felt they too should have asserted themselves more, especially against the Indian spinners.

"I did think we could probably have taken on the Indian spinners just a little bit more...But again, they were building and building nicely.

"I think we've got to realise that there are two ways to always skin a cat. And we've had success by taking it deep and then cashing in at the back end."

Their bowling also lacked fire against India.

Pace spearhead Shaheen Afridi has not been at his best since returning from a knee injury, while spinner Shadab Khan's lack of success in the middle overs has been a talking point of late.

Arthur said they were trying to address those issues.

"Look, it'd be remiss of me to discuss it out here, but we've been doing some work with them," the former Australia coach said.

"The key for us now is getting our players to remain calm. It's getting our players to focus on the next game, and it's to build them up and make sure that they go into that next game thinking they can run through a brick wall."