Kolkata, May 7 (PTI) Left-arm wrist spinner Noor Ahmad exploited the turning conditions brilliantly, picking up 4/31, to restrict Kolkata Knight Riders to 179 for 6, as Chennai Super Kings' spin trio dominated the middle overs in the home team's must-win IPL clash here on Wednesday.

After cruising at 67/1 at the power-play, KKR choked with Ahmad turning the tide.

The Afghan spinner broke KKR's rhythm immediately after the powerplay, striking twice in one over.

First, he dismissed Narine (26 off 17 balls; 4x4, 1x6), beaten in flight and stumped brilliantly by MS Dhoni. Four balls later, Angkrish Raghuvanshi edged behind to give CSK a double breakthrough.

KKR lost further momentum as the boundaries dried up -- at one stage, they went 24 balls without a single four -- in the middle overs.

Their hopes rested on Andre Russell, fresh from a match-winning fifty in the previous game.

The explosive Jamaican shifted gears, smashing Ravindra Jadeja for two fours and a six, and then launched Ahmad into the stands with a massive six off a googly.

But Ahmad had the last laugh, deceiving Russell (38 off 21 balls) with another well-disguised googly to end his dangerous knock.

In his final over, Ahmad also removed Rinku Singh, wrapping up a terrific spell that broke KKR's backbone.

From 67/1 in six overs, KKR managed just 112 runs in the next 14 overs, as CSK spinners collectively gave away only 55 runs in last five overs, throttling the scoring on a sluggish, turning track.

Opting to bat, KKR, hanging by a thread in the playoff race, came out with full intent.

Rahmanullah Gurbaz opened with a boundary and launched Anshul Kamboj over midwicket in the second over.

Though Kamboj dismissed him in the same over, it had little impact as Ajinkya Rahane and Sunil Narine swung freely, adding 67 runs in the powerplay.

Rahane, who was dropped on 15 by Matheesha Pathirana off Kamboj, capitalised on the reprieve.

Narine, meanwhile, took on Ravichandran Ashwin, smashing two fours and a six in his opening over.

But once the field spread out, CSK's spin trio took complete control.

Jadeja applied pressure with a tight spell of 1/34, while Ashwin was the most economical, returning 0/19 from his three overs, extracting sharp turn and bounce. PTI TAP PDS