Worcestershire's batsmen were given a searching examination today by the New Zealand attack and lost five wickets in the pre-lunch session at New Road.
Alexei Kervezee made an accomplished 33 and skipper Daryl Mitchell continued to show the sort of defiance evident at Edgbaston earlier in the week.
But Matt Henry, Neil Wagner and Ben Wheeler posed plenty of questions as Worcestershire reached 143-6 off 53 overs by lunch – 118 in arrears with Ross Whiteley 21 not out and Ben Cox eight not out.
Worcestershire resumed on 65-1 against an opening attack of Henry and Wagner with Moeen Ali unbeaten on 20 and Mitchell 15 not out.
Moeen added only three more runs before he clipped Wagner to square leg where Doug Bracewell held onto the catch in the second over of the day.
Tom Fell (0) was undone by a delivery from Henry which lifted and was caught behind by keeper BJ Watling.
Alex Gidman produced the first boundary of the morning via a flowing cover drive at Henry's expense.
But in the same over Gidman was bowled by a ball of full length from Henry for five.
Kervezee collected two boundaries to third man off Corey Anderson who replaced Wagner.
Mitchell defied the Black Caps bowlers for nearly two and a half hours in making 22 before he was the victim of a good catch at third slip by Martin Guptill off Bracewell.
The 100 came up in the 42nd over and Kervezee produced two of the strokes of the morning in cover-driving Wheeler for successive fours.
Whiteley greeted the return of Henry to the attack with a lofted off drive for four to get off the mark and square drove the same bowler for another boundary.
Kervezee moved onto 33 before being bowled by Wheeler with the total 130-6 in the 48th over.
The partnership with Whiteley was worth 38 in 11 overs.