Their campaign in tatters after their 21-run loss to Hyderabad, Jharkhand not only needed a big win against Jammu and Kashmir but wanted Hyderabad to lose to Services.
Hyderabad had cleared Dhoni's hurdle at Eden Gardens in the afternoon by losing to Services after they were shot out for 88 in 28.5 overs.
At the Bengal Cricket Academy here, about 50 kilometres from Kolkata, Dhoni entertained his fans with an unbeaten 19 off 17 balls (2x4, 1x6) to take his team to a resounding victory.
Chasing 185, which was possible after Shahbaz Nadeem's (5/42) second five-wicket haul bowled out Jammu and Kashmir in 43 overs, Dhoni finished the game in his trademark style, with a huge six over fine leg.
He pulled Mehjoor Ali to seal the chase with 15 overs to spare as Jharkhand joined table toppers Karnataka in the quarterfinals from Group D.
The knock-out round will be played in Delhi from March 13-18. Dhoni did not have to bat in their facile win over Services here, leaving the crowd here disappointed.
Therefore, the biggest cheer came on 156 for three when the former India captain walked into the middle.
The excitement shot up when Singh removed the Jharkhand topscorer Kumar Deobrat (78 from 94 balls; 5x4, 4x6) three balls later.
But as anticipated, Dhoni dished out the finishing shot on a day he made some clever decisions with left-arm spinner Shahbaz Nadeem (5/42) returning with his second five-wicket haul.
This was Deobrat's first game of the meet after being brought in place of Virat Singh, while Rathour made his List A debut in place of Anand Singh on a day Dhoni made three changes in the must-win match.
The third change was of seamer Monu Kumar who replaced Jaskaran Singh and conceded just 23 runs from his seven overs.
Having won the toss, Dhoni was quick to put Jammu and Kashmir in as they were 39/2 inside 12 overs with Varun Aaron and Rahul Shukla claiming a wicket each.
Jharkhand's wobbly fielding once again was a big setback for Dhoni as Ishan Jaggi dropped opener Owais Shah on zero as he was quick to remove him from the position.
The drop proved costly as the left-hander revived Jammu and Kashmir with his careerbest 59 in a 66-run partnership with skipper Parvez Rasool (45).
Shah was patient in his knock as he took 106 balls and hit five fours but introduction of spin in Nadeem and offspinner Kaushal Singh (2/31) dented their revival.
Nadeem gave the breakthrough after Rasool tried to sweep and play across the line to top-edge to Rahul Shukla at fine leg, before Shukla claimed two wickets in two overs to derail their opponents as the leftarm spinner now has 14 wickets from six matches.
The left-arm spinner dismissed Shah off his own bowling as Jammu and Kashmir lost eight wickets in 79 runs.
Kalyani: Jammu and Kashmir 184; 43 overs (Owais Shah 59, Parvez Rasool 45; Shahbaz Nadeem) lost to Jharkhand 185/4; 35 overs (Kumar Deobrat 78, Shasheem Rathour 36, Saurabh Tiwary 30, MS Dhoni 19 not out) by six wickets.
Eden Gardens: Hyderabad 88; 28.5 overs (Chama Milind 32; Diwesh Pathania 4//21, Sachidanand Pandey 3/22, Suraj Yadav 3/36) lost to Services 92/5; 20.2 overs (Gaurav Kochar 24; Mohammad Siraj 2/31) by five wickets.