Group A

Graeme Swann went a long way to proving his fitness ahead of the West Indies series with three wickets to help Nottinghamshire open their campaign with a comprehensive eight-wicket victory against Leicestershire at Trent Bridge. Swann played a key part in the visitors' middle-order collapse after Andre Adams had removed both openers. Swann also had a hand in the first of three run-outs when he deflected James Taylor's drive into Boeta Dippenaar's stumps at the non-strikers' end and from 108 for 3 the innings fell away rapidly. Samit Patel producing a direct hit to dismiss Wayne White and make a point to the England selectors after his omission in West Indies for being unfit. Taylor was left stranded on 44 when Swann had Andy Harris stumped. The target was a cakewalk for the home side. Mark Wagh hit an unbeaten 68, adding 106 with 20-year-old Alex Hales, and the win was completed with more than 20 overs to spare.

Worcestershire gained revenge for their heavy Championship defeat by turning over Hampshire by 53 runs in a high-scoring encounter at The Rose Bowl. Moeen Ali, seen by many as the man who needs to fill the hole left by Graeme Hick, showed his talent with 125 off 109 balls as Worcestershire powered to 320 for 8. Steven Davies got the innings off to a positive start with 50 and Ben Smith (70) combined alongside Ali to add 165 for the fourth wicket. Hampshire made a good first of the chase early on with Michael Lumb and John Crawley adding 116 in 21 overs, but once Gareth Batty broke through the innings fell away. Spin played a key part with Ian Fisher removing Michael Carberry before Batty ran through the lower order with a career-best 5 for 35, including Crawley for an even hundred. There was one sour note for Worcestershire as Kabir Ali picked up a hamstring strain.

Group B

Craig Kieswetter's outstanding start to the season continued with his unbeaten 138 enabling Somerset to stroll to victory against Warwickshire at Edgbaston and meaning Ian Bell's own eye-catching contribution went in vein. Bell is doing everything right in his quest to win back an England spot, following his Championship 172 with 108 here, but it wasn't enough to quell Somerset's strong top order. Kieswetter hit 150 in the four-day game and combined in a match-clinching stand of 188 with Zander de Bruyn, who earlier played his part with the ball by claiming 3 for 30. Warwickshire had been well placed on 122 for 1 when de Bruyn trapped Jim Troughton (53) lbw and he also sent back Rikki Clarke and Tim Ambrose. Although Bell reached his ton off 118 balls the home side couldn't recover sufficiently.

Group C

Michael Vaughan showed glimpses of form, but he was overshadowed as Yorkshire wrapped up an 80-run victory against Durham, one of the pre-tournament favourites, at Chester-le-Street. Vaughan cracked some handsome boundaries during his 44-ball 43 before being bowled through the gate by Gareth Breese and it was left to Jacques Rudolph (73) and Gerard Brophy (66) to supply the key innings. Brophy provided late impetus, needing 48 balls for his runs, with Steve Harmison feeling the force of his assault as his eight overs cost 63. Durham slipped to 48 for 3 in reply before a stand between Will Smith and Dale Benkenstein - the current and former captains - revived the chase. However, Smith dragged on against Ajmal Shahzad and Ian Blackwell soon fell to Adil Rashid as he toe-ended a return catch.

Is this the start of another successful John Bracewell era at Gloucestershire? Of course it's too early to tell, but a seven-wicket win against Sussex at Bristol is a decent way to start. Gloucestershire's strength is in their batting and strong half-centuries from Craig Spearman and Chris Taylor guided the chase of 228 as they added an unbroken 122. Sussex's innings had been a stop-start affair with Matt Prior hitting 50 and Luke Wright a brisk 40 off 41 balls, but it needed Michael Yardy's 58 to lift them over 200 after Vikram Banerjee claimed three wickets. He removed Prior then added Rory Hamilton-Brown and Robin Martin-Jenkins in two balls.

Group D

Lancashire's strong bowling attack proved too much for Glamorgan at Old Trafford as the home side eased to an 80-run success. James Anderson was made available by England, but it was Kyle Hogg and Sajid Mahmood who did most of the damage as they shared six wickets. Hogg was outstanding with the new ball and his three-wicket burst left Glamorgan floundering on 21 for 4 when Tom Maynard was caught behind. The middle tried to stage a recovery - Mark Wallace hit 60 - but Mahmood and Glen Chapple went through the lower order. Tom Smith had earlier justified his move to opener with 66, a score matched by Faf du Plessis less than 24 hours after he arrived from South Africa and although 241 wasn't a huge total it proved more than enough.

Defending champions Essex laid down a marker for their season with an expertly-paced run chase against Northamptonshire as they completed a seven-wicket win with 10 balls to spare at Chelmsford. They made a potentially testing chase look comfortable, fired by Mark Pettini's 57 and an authoritative 76 from Varun Chopra. The match-sealing partnership, however, came from two old heads as Matt Walker - who has arrived from Kent - and Grant Flower, last year's hero in the final, added 88 at a brisk rate. They killed the game off in the batting powerplay as a disappointing Northants attack struggled to stem the run-rate. They had batted with more conviction after being put in, recovering well from 66 for 4 with three middle-order half-centuries. Steven Crook top-scored with a career-best 72, but although Essex were missing a number of key players - including Ravi Bopara, Graham Napier and Danish Kaneria - they proved too strong.