England in deep trouble at 24-3 against Pakistan after gritty Shakeel century
England came in looking to erase a deficit of 77 but had no answers for the Pakistan spinners on a turning pitch.
Sajid dismissed Ben Duckett for 12 and Noman Ali removed Zak Crawley (two) and Ollie Pope (one) in the space of five runs.
When bad light ended the second day's play with five overs remaining, Joe Root and Harry Brook were at the crease on five and three respectively.
England still need 53 runs to avoid an innings defeat with seven wickets in hand and three days left to play.
The series is tied at 1-1 after England won the first Test by an innings and 47 runs while Pakistan took the second by 152 runs, both in Multan.
On another day dominated by spin, Shakeel's brilliant 134 was the highlight, pulling Pakistan withing touching distance of a first home Test series win since they defeated South Africa in February 2021.
Shakeel anchored Pakistan's innings, lifting them from a precarious 177-7 to 344 all out.
The left-hander held Pakistan's innings together with a gritty knock spread over 322 minutes and 223 balls, hitting just five boundaries.
Leg-spinner Rehan Ahmed was the pick of the England bowlers with 4-66 while Shoaib Bashir finished with 3-129.
The 29-year-old Shakeel defied England with an eighth wicket stand of 88 alongside Noman who made 45 before falling in the final over ahead of the tea break to spinner Bashir.
Shakeel added another 72 for the ninth wicket with Sajid who scored an unbeaten career-best 48.
Shakeel was finally caught off a miscued pull off pacer Gus Atkinson while Ahmed dismissed the last man Zahid Mahmood for nought.
The visitors looked to be in control when young spinner Ahmed bagged three quick wickets to leave Pakistan teetering at the end of the first session.
England were eyeing a lead after Ahmed's burst left Pakistan on 187-7 at lunch but the Shakeel-Noman stand turned those expectations into frustration.
Shakeel batted with composure and reached his fourth Test hundred with a single off Rehan in a resistance-packed innings.
Noman - surviving a leg-before decision on review and a dropped catch off Root - assisted Shakeel admirably, hitting a six and two fours as the duo helped Pakistan add 80 in the second session.
Rehan sent Mohammad Rizwan (25), Salman Agha (one) and Aamer Jamal (14) back to the pavilion and threatened to derail Pakistan.
England's frontline spinners Jack Leach and Bashir could not extract the same sharp turn from the pitch as rival Sajid Khan, who took 6-128 on Thursday.
Pakistan resumed the day at 73-3 in search of a lead to press for a series win.
But Shakeel was the only batter able to continue after reaching double figures.