Younus boosted Pakistan's quest with an unbeaten knock of 123 off 117 balls to help his side overhaul India's total of 308-7 for their fifth successful run chase in one-day internationals, the fourth against their arch-rivals.
The win helped Pakistan stay in the tournament and leaves them hoping that India lose to Sri Lanka on Thursday. The hosts would then seek to beat Bangladesh on Friday.
India, on four points from two matches with one win and two carry over points from the first round, need a win Thursday to reach the July 6 final.
Titleholders Sri Lanka have already qualified for the final with wins over Pakistan and Bangladesh.
Younus, declared man-of-the-match, shared a crucial unbroken 144-run stand for the third wicket with stand-in captain Misbah-ul-Haq who hit seven boundaries and a six in his unbeaten 62-ball 70.
Misbah hit paceman Praveen Kumar for a boundary to bring victory with 4.3 overs to spare.
The 30-year-old Younus hit Kumar for his ninth boundary to reach his fifth one-day hundred off 99 balls.
Younus, who also completed 5,000 one-day runs when on 36, hit eleven fours and a six to outshine Indian captain Mahendra Singh Dhoni's 76 which lifted India to an imposing total.
Pakistan raced to a solid start of 65 before Salman Butt (36) was run out in the eighth over. Opener Nasir Jamshed, who came in after captain Shoaib Malik was ruled out due to dehydration, hit an aggressive 53 with nine boundaries.
When Jamshed retired hurt after suffering cramps, Younus and Mohammad Yousuf (21) took Pakistan to 165 when Yousuf was bowled by leg-spinner Piyush Chawla.
That did not deter Younus who in company of Misbah brought up the win.
Earlier India almost spoiled a robust start of 88 provided by Virender Sehwag (49) and Gautum Gambhir (35) but Dhoni added 112 runs for the fifth wicket with Rohit Sharma (58) to steady the innings.
Sehwag smashed six boundaries and two sixes during his 33-ball knock, while Gambhir hit four boundaries before Pakistan hit back taking three wickets off just nine balls in the space of three runs.
Paceman Rao Ifktihar, who finished with 3-51, had Gambhir before Abdur Rauf, one of three changes in the Pakistan team, removed Sehwag and Suresh Raina (one).
Yuvraj hit four boundaries and a six in his 32-ball 37 but his fall left India struggling at 129-4
Sharma and Dhoni steadied the innings through their 139-ball partnership. Sharma hit four boundaries during his 71-ball knock.
Dhoni miscued a heave off Sohail Tanveer in the penultimate over and was caught by wicket-keeper Sarfraz Ahmed. He added 41 for the seventh wicket with Irfan Pathan who finished 38 not out.