India spun out Afghanistan for 159 and needed only 33 overs to reach the winning target in the Asia Cup.
Afghanistan succumbed on a Sher-e-Bangla Stadium pitch aiding slow bowling, the Afghans' batting weakness.
N Zadran c Kohli b Jadeja 31
N Mangal b Shami 5
R Shah lbw b Jadeja 9
A Stanikzai c Mishra b Jadeja 5
N Zadran c Binny b Ashwin 5
M Nabi c Karthik b Jadeja 6
M Shahzad lbw b Ashwin 22
S Shenwari lbw b Shami 50
M Ashraf c Kohli b Mishra 9
S Zadran lbw b Ashwin 1
D Zadran not out 2
Total: (all out; 45.2 overs) 159
Fall of wickets: 1-30, 2-54, 3-55, 4-60, 5-64, 6-83, 7-95, 8-111, 9-137, 10-159
A Rahane lbw b Ashraf 56
S Dhawan b Nabi 60
R Sharma not out 18
K Karthik not out 21
Total: (2 wickets; 32.2 overs) 160
Fall of wickets: 1-121, 2-123
Left-armer Jadeja grabbed 4-30, offspinner Ravichandran 3-31 and legspinner legspinner Amit Mishra 1-21.
Afghanistan handled India's pacemen intially to reach 52-1 after 11 overs.
But for the next 25 overs of relentless spin, the Afghans were tormented by the appreciable turn.
Jadeja took two wickets with his first three deliveries. He had 3-3 off two overs, and should have had a fourth wicket in his third over, but a regular catch of Najibullah Zadran was dropped by Kohli in the slips.
Shami was hit for 10 in the 37th over, and India reverted to three more overs of spin, in which the ninth wicket was taken.
Afghanistan then hung on for 7.2 more overs, as Samiuallah Shenwari scored a fighting 50 to help his side pass 150.
Shenwari's fifth half-century in 31 games included six fours and a six off 73 balls.
During India's chase, Dhawan and Rahane showed a fine understanding, and often stole singles when they found it difficult to work the ball away.
Dhawan, dropped at point by Shenwari off seam bowler Dawlat Zadran on 28, slammed four fours and one six in his seventh ODI half-century.
He was out one over before Rahane, who was promoted to opener in place of Rohit Sharma, and hit five fours for his fifth ODI half-century. Sharma and Dinesh Karthik finished off the chase.
The result allowed India to bow out on a winning note after being edged to Saturday's final by Sri Lanka and Pakistan.
"It's hard to motivate yourselves when you ... are out of contention for the final. Being more relaxed worked for us, we were quite tense in the earlier games,'' said Virat Kohli, India captain in the absence of Mahendra Singh Dhoni.
There was a prideful exit for fast-improving Afghanistan, too, after an historic win over Bangladesh in their first Asia Cup.
"There was a big celebration in Afghanistan (after the win over Bangladesh)," captain Mohammad Nabi said.
"If there are more matches against full members, it will be a good experience for Afghanistan."