Essex 161 for 5 (Cook 71, Foakes 51) beat Sri Lankans 146 for 9 (Chandimal 31, Newby 3-36) by 22 runs (D/L method)
Sri Lanka were given a harsh introduction to the challenge of English conditions as they subsided to a 22-run loss on the D/L method on a damp night in Chelmsford.
In dank conditions that could hardly have differed more from those found in the sub-continent, Sri Lanka were undone by a second-string attack that included three man making List A debuts for Essex and, unlikely though it sounds, a fine catch by Monty Panesar.
Indeed, while Sri Lanka might have expected to struggle against seam bowlers in these conditions, they lost four wickets to the Essex spinners with Panesar, playing his first List A game since August 2012, taking two wickets as reward for a spell full of variation; not a description that could always be applied to him.
But perhaps his key intervention came in the field. With Dinesh Chandimal threatening to turn the game in his side's favour, Panesar held on to a sharp catch at long leg off a full-blooded hook to all but seal the match.
In truth, Panesar misjudged the chance a little, over-running the ball and almost seeing it sail well over him. But so impressive was his adjustment that he was able to cling on to the ball far above his head and end Sri Lanka's last realistic hope of victory.
It meant that an Essex side missing almost its entire first-choice attack beat the side crowned World T20 Champions just over a month ago in a match reduced by rain to 21-overs a side.
It would be wrong to read much into this defeat, though. After rain caused a five-hour break in play, Sri Lanka opted to give several part-time bowlers a run-out - Lahiru Thirimanne had previously only bowled 60 deliveries in his List A career - and conditions were probably on the borderline of acceptability with a slippery outfield and a pitch offering substantial help to the seam bowlers.
Oliver Newby, a loan signing from Lancashire, made the key inroads. After having Kusal Perera trapped leg before, he produced an unplayable delivery - one that pitched on middle and moved like a fast leg-break - to take the edge of Mahela Jayawardene's bat.
With Tillakaratne Dilshan bowled by what appeared to be a deliberate arm ball from Panesar - he changed his action often and appeared to push that delivery into the batsman with a lower arm - and Greg Smith holding one back to deceive Thirimanne and then seeing Angelo Mathews held in the outfield, Sri Lanka were never able to exploit an attack that included Matt Salisbury, a 21-year-old on List A debut, and Reece Topley, who was enjoying his first bowl of the season following a stress fracture.
Earlier Alastair Cook bludgeoned his way to a half-century to help Essex overcome a poor start. For a good portion of his innings, Cook mistimed the ball horribly, surviving near misses on 32 and 37 and barely managing a clean stroke. It took him until the 19th over of the innings to register his 50.
But he gained in fluency as his innings progressed and, having reached his 50 from 44 balls with a scooped sweep for six off Perera, he embarked on a run that saw him score 22 from five deliveries. If the highlight was another scooped six, he also demonstrated his growing range of strokes with a powerful pull for four and a drive down the ground.
But the most eye-catching batting of the innings came from Ben Foakes. The 21-year-old has been seen as a future England keeper for some time and here showed his batting class with a half-century from just 30 balls. He slog-swept successive sixes off Dilshan and timed the ball unusually well off his hips. It was only the second List A half-century of his career, but contained a good deal of promise.
Cook and Foakes added 82 for the fourth-wicket in nine overs to help Essex recover from the depths of 21 for 3 in the seventh over. After Mark Pettini was trapped in front, Smith's loose drive was beaten by a straight one and Ravi Bopara was caught on the crease by one that nipped back having been set up by one that nipped away by the impressive Suranga Lakmal. His first four overs cost only eight runs.
But while Sri Lanka conceded only 46 from their first 10 overs, the final 11 of the Essex innings cost 115. In tricky conditions, it was to prove too much.
Essex will be further heartened by the arrival of Jesse Ryder on Thursday. The New Zealand batsman's arrival has been delayed by visa issues, but is expected to be available for the county's first T20 Blast match. Essex also hope that David Masters will be fit to return from injury.