Kolkata beat Mumbai in the opening match of the 2014 Indian Premier League in Abu Dhabi, United Arab Emirates.
The Knight Riders, who won the toss and elected to bat, made 163-5 at the Sheikh Zayed Stadium.
In reply the defending champions were restricted to 122-7, with the Indians slipping to a 41-run defeat.
South African veteran Jacques Kallis led Kolkata to a competitive total, as he made 72 from 46 balls.
The 38-year-old put on 131 for the second wicket with Manish Pandey after the 2012 champions lost skipper Gautam Gambhir in the second over for a duck.
Pandey made 64 from 53 balls before becoming Lasith Malinga's second victim in the 17th over.
Robin Uthappa was outwitted by Zaheer Khan at the end of the 18th over after making just one before World Cup-winning captain Malinga returned to pick up the scalps of Kallis and Shakib Al Hasan (one) in the penultimate over.
Sri Lankan star Malinga finished 4-for-23, but Corey Anderson's final over went for 14.
|G Gambhir*||b Malinga||0||8||0|
|JH Kallis||c Anderson b Malinga||72||46||5/3|
|MK Pandey||b Malinga||64||53||6/2|
|RV Uthappa†||c Sharma b Khan||1||2||0|
|YK Pathan||not out||4||0||0|
|Shakib Al Hasan||c Sharma b Malinga||1||2||0|
|SA Yadav||not out||13||3||0|
|Extras||(lb 4, w 4)||8|
Mumbai's reply started slowly, and they only reached 54-2 at halfway, losing openers Mike Hussey and Aditya Tare in the process.
Ambati Rayudu and Rohit Sharma shared a half-century partnership but were left needing 69 off the final five overs.
|MEK Hussey||b Narine||3||13||0|
|AP Tare||c & b Shakib Al Hasan||24||22||2/1|
|AT Rayudu||st Uthappa b Narine||48||40||4/0|
|RG Sharma*||c Kallis b Morkel||27||20||0/1|
|KA Pollard||not out||6||8||0/0|
|CJ Anderson||b Narine||2||8||0/0|
|H Singh||b Narine||0||2||0/0|
|CM Gautam||st Uthappa b Chawla||7||7||1/0|
|R Vinay Kumar||2||0||15||0|
|Shakib Al Hasan||4||0||29||1|
Piyush Chawla's leg-spin kept things tight, while IPL star Sunil Narine picked up cheap wickets with his probing tweak to finish with tidy figures.
The opening 20 games of the 56-match regular-season phase are being held in the United Arab Emirates.
After each of the eight teams have played 14 matches, the top four progress to the play-offs, with the competition coming to a conclusion in Mumbai on June 1.