The five-time champions bowled Afghanistan out for 207 in 38.2 overs on a warm day in Bristol and then made steady progress, reaching their target with more than 15 overs to spare, with Warner 89 not out.
Pakistan kept alive their chances of reaching the World Cup semi-finals on Wednesday, cruising to a six-wicket win against previously unbeaten New Zealand at Edgbaston.
"Congratulations especially go to Babar, Haris and Shaheen for their brilliant performances," said Imran, who led Pakistan to victory in the 1992 World Cup.
The two-time champions, who are unbeaten in their six outings so far, including a washed-out game, fielded an unchanged side after their narrow victory against Afghanistan.
Left-arm seamer Shaheen Afridi (3-28) had helped reduce the Black Caps to 46-4 and 83-5, when Kane Williamson was out for 41.
Mavericks Cricket Club routed TNS Pulse Secure by 80 runs in the final of the JK White sponsored Dubai Cricket Council’s Ramadan League at the Sevens ground on Sunday night.
Tendulkar's views though haven't gone down well with Dhoni's ardent fans and they have taken to social media to make their disappointment known.
Pakistan head coach Mickey Arthur has claimed that he was feeling so low and disappointed after his team's loss to India in the ongoing World Cup that he wanted to "commit suicide".
India's Mahendra Singh Dhoni fuelled retirement speculation on Tuesday after sharing his dream of becoming a painter, although his ambitions for a career change seemed far from serious.