Pakistan vs New Zealand, 3rd Test, Day 4, Abu Dhabi
Yasir Shah dismissed William Somerville early in the day to reach 200 Test wickets. He became the quickest to the landmark - reaching there in 33 Tests.
Shaheen Afridi then dismissed Ross Taylor to leave New Zealand in trouble at 60 for 4.
Williamson and Nicholls started building the lead and played out the entire second session without any damage.
Williamson registered his 19th Test ton to frustrate Pakistan.
Nicholls too got to his half-century soon after as New Zealand continued to build a substantial lead.
Williamson stayed unbeaten on 139 as New Zealand ended the day on 272 for 4 with a lead of 198.