On a pitch offering little encouragement for the faster bowlers, Shah's role as both a stock bowler and premier wicket-taker were in evidence as he remained a perennial threat through an extended morning session in which he accounted for 11 of the 33 overs bowled.
Entrusted with the ball at the start of the day by captain Misbah-ul-Haq, the premier spinner did not disappoint, breaking a 43-run opening partnership between Kraigg Brathwaite and Kieran Powell.
With Brathwaite plodding along in his usual stoic manner at the other end, new batsman Shimron Hetmyer sought to seize the initiative from the bowlers. His intentions were clear when he hoisted Shah for the only six of the innings so far.
But the bowler exacted swift revenge as an original "not out" verdict by standing umpire Bruce Oxenford for an appeal for a leg-side catch by wicketkeeper Sarfraz Ahmed was overturned on review when television replays revealed a faint touch of the ball onto the batsman's glove.
Shai Hope (15 not out) is expected to be joined in the middle by fellow-Barbadian Roston Chase when play resumes in the afternoon.
Shah has now taken 20 wickets in the series.
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