Bob Willis Trophy: Sam Cook stars with ball for Essex against Middlesex

Sam Cook's 4-27 was his best haul in this year's Bob Willis Trophy

Sam Cook returned season-best figures as Essex's Bob Willis Trophy final hopes remained on track with 15 wickets falling on day one at Chelmsford against Middlesex.

Fast bowler Cook took 4-27 and was backed up by new-ball partner Jamie Porter (3-55) and spinner Simon Harmer (3-34) as Middlesex were dashed out for 138 in 53.3 overs.

But, in reply, Tim Murtagh and James Harris each took two wickets to leave reigning county champions Essex 108-5 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.

• Relive Sunday's action in the Bob Willis Trophy

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 Stevie Eskinazi, they had their first point on the board inside half an hour.

Max Holden, who had scored a century in the Vitality Blast fixture at Chelmsford last week, was caught behind to Cook's second delivery.

Nick Gubbins and Sam Robson both fell to Porter to leave Middlesex 18-3 - the former lbw and the latter, following back-to-back boundaries, bowled while leaving.

Eskinazi was caught behind off his inside edge after sticking around for 15.

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 Harmer behind and Harris, following a patient top score of 34, was lbw to Sam 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 Blast defeat b Surrey at the Kia Oval at 21:20 BST on Saturday, with five players featuring in both matches. Having scored 113-9 in the T20, they had a combined score of 251-19 in about 20 hours.

The pitch had offered nip, plenty of carry and offered the spinners turn, but it was not a wicket that would suggest the number of wickets that fell - though the trend continued into the Essex innings.

On the back of an unbeaten 129 on his last outing, Alastair Cook could only manage six 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 with Murtagh the chief instigator, jagging 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 but Walter stood tall throughout as he made his new role as opener his own with a well-made 43.

He was castled by Harris to leave Essex on 87-5 before Wheater and Ryan ten Doeschate helped their side head towards a first-innings lead, albeit still a long way from any batting bonus points.

Match report supplied by PA Media.