Essex 108 for 5 (Walter 43) trail Middlesex 138 (S Cook 4-27) by 30 runs

Sam Cook returned season-best figures as Essex's Bob Willis Trophy final hopes remained on track despite 15 wickets falling on day one at the Cloudfm County Ground, Chelmsford.

Fast bowler Cook celebrated analysis of 4 for 27 as he formed a formidable trident with new-ball partner Jamie Porter and spinner Simon Harmer as Middlesex were dashed out for 138 in 53.3 overs. But in reply, Tim Murtagh and James Harris both took two wickets to leave reigning county champions Essex 108 for 5, despite Paul Walter's 43.

Essex are heavy favourites to top the South Group but to qualify for the Lord's final later this month they need to score more points than either the winner of the Central or North section. They will likely need to get a bonus point more than northern leaders Derbyshire, if both teams were to win.

That quest for points started off well as they received the full three bowling points on offer by skittling Middlesex. Having been put in the field by Middlesex captain Steve Eskinazi, they had their first point on the board inside half an hour.

Max Holden, who had scored a century in Vitality Blast fixture at Chelmsford earlier this season, was caught behind to Cook's second delivery. Nick Gubbins and Sam Robson both fell to Porter to leave Middlesex 18 for 3 - the former lbw and the latter, following back-to-back boundaries, was bowled while leaving. Eskinazi was then caught behind off his inside edge after sticking around for 15.

Harmer was brought into the attack in the 18th over from his customary River End and immediately found massive turn. Although the Bob Willis Trophy's leading wicket-taker didn't need to use the facilities when Martin Andersson slapped a full toss to midwicket.

Former Essex loanee Robbie White was the sixth batsman to depart when he edged Porter to Alastair Cook at first slip - giving Essex a second bonus point and Porter his 350th first-class scalp.

The tumble continued as John Simpson edged Porter behind and Harris, following a patient innings high 34, was lbw to Cook. The innings closed when Thilan Walallawita was adjudged to have edged behind and Blake Cullen handed wicketkeeper Adam Wheater his fifth catch of the day.

Middlesex had only finished their Vitality Blast defeat to Surrey at the Kia Oval a 9.20pm on Saturday evening, with five players featuring in both matches. They had travelled immediately after that match. Having scored 113 for 9 on the T20 and then been rolled for 138, Middlesex had a combined score of 251 for 19 in around 20 hours.

The pitch had nip, plenty of carry and offered the spinners turn, but it certainly wasn't anything out of the ordinary. But the trend for quick wickets would continue into the Essex innings.

On the back of an unbeaten 129 on his last outing, Cook could only manage 6 as he edged to first slip, handing teenager Cullen a memorable third professional wicket in his second appearance.

Essex then lost three wickets in 19 balls to continue the instability - with Murtagh the chief instigator. The veteran jagged a delivery in to take Tom Westley's off stump before Dan Lawrence nicked behind while moving down the wicket. Harris then took over to have Feroze Khushi lbw.

Walter stood tall throughout, though, as he made his new role as opener his own with a well-made 43. But he was castled by Harris to leave Essex on 87 for 5 - with Wheater and Ryan ten Doeschate helping their side head towards a first-innings lead, albeit still a long way from adding any batting bonus points to their tally.