Chasing Kolkata's 169, Deccan could reach only 149 for six, despite a battling 45-ball 54 from Shikhar Dhawan.
Batting first after losing the toss Kolkata made a positive start reaching 73 by halfway for the loss of Eoin Morgan (14), whose leg stump was sent cartwheeling by Daniel Christian.
Jacques Kallis and Gautam Gambhir combined for a 43-run stand before getting out in quick succession off Amit Sharma and Pragyan Ojha respectively.
Having reached 84 for three by the 12th over, the stage was set for an onslaught from Pathan and Manoj Tiwary, who hit a flurry of boundaries and sixes.
Kolkata leapt to 150 from 100 in just 24 balls as the Deccan bowlers wilted under pressure and dropped at least three catches off rampaging Pathan.
The fourth-wicket pair added 80 off just eight overs before Tiwary (33 off 28 balls) holed out in the deep off Dale Steyn's last over, but Pathan's 47 off 26 balls boosted Kolkata to 169 for four.
And Pathan credited his captain's encouragement for scoring heavily.
"Mashallah, the ball was struck very well today," he said at the end of the game after receiving the man-of-the-match award. "The captain [Gambhir] told me to just play my game."
In response, Sunny Sohal, along with Dhawan, took the total to 41 in just the sixth over before a double strike from Iqbal Abdulla pegged the visitors back.
Sohal (26 off 20 balls) was lured to hit one straight to Morgan at cover, while new man Kumar Sangakkara, the captain, handed an even easier catch to Kallis two balls later.
Deccan moved to 68 after 10 overs and Rajat Bhatia then dealt a double blow removing Cameron White and Christian in the same over, although the latter was given out lbw despite a clear inside edge.
Deccan's chase lost direction thereafter as neither Dhawan nor Dwaraka Ravi Teja could replicate the heroics of Pathan and soon the requirement was 62 off 30 balls.
Dhawan fought well and reached his seventh IPL half-century off 41 balls, but Kallis removed him in the 18th over and by then Brett Lee had seen off Teja (30 off 22).
Bharat Chipli (12 not out off seven) and new man Mishra could only reduce the margin of defeat as Kolkata went joint top with Mumbai.
At the end of the game, Sangakkara had only his players to blame for their sixth defeat. He said: "We should have limited them to around 150-155. Our openers tried hard and delivered a solid start.
"We need to hold our catches, bowl well in the death overs and build on solid starts.
"Kolkata outplayed us and it's back to the drawing board for us," he added.
* Compiled by The National staff with agencies