Worcestershire vice-captain Joe Leach picked up four wickets in the space of 23 balls on day three of the weather-hit Specsavers County Championship clash with Essex at New Road.
Leach took full advantage of the second new ball as he produced the sort of spell which helped him to finish as the County's leading wicket-taker in the Championship with 59 victims last summer.
It enabled Worcestershire to pick up two bowling bonus points after Essex had resumed on 335-2 from 90 overs.
Leach made his first breakthrough when Ravi Bopara played back and had his middle stump flattened without adding to his overnight 48. One of the bails flew 25 yards towards the boundary.
Daniel Lawrence failed to open his account before driving at Leach and nicking through to Tom Kohler-Cadmore at first slip.
Jesse Ryder (0) was trapped lbw by Leach who then produced a stunning low one-handed catch of his own bowling to end England Test skipper Alastair Cook's fine innings on 142.
Cook struck one six and 22 fours in his 284 ball innings.
James Foster and Ryan ten Doeschate added 73 in 10 overs to secure maximum batting points for Essex with Worcestershire picking up two bowling points.
Leach was rested after a morning spell of 9-2-34-4 and his replacement Ed Barnard accounted for Ten Doeschate, lbw for 28.
Jack Shantry was hit for successive sixes by Graham Napier but in the same over he holed out to Matt Henry at long on for 16.
Leach came back to complete his nap hand when David Masters (1) was on the end of a superb diving catch at extra cover by Barnard at which point Essex declared on 451-9.
Leach finished with 5-115 from 27.4 overs.
