England raced to 46-2 at lunch on the fourth day of the first Test against Pakistan Sunday after spinner Will Jacks took six wickets on his debut to help the tourists gain the upper hand.
Jacks grabbed 6-161 to help England dismiss Pakistan for 579 and give his side a 78-run first-innings lead.
At the break, Zak Crawley and Joe Root were at the crease with 24 and four respectively, pushing the lead to 124 with eight wickets intact.
The tourists -- playing their first Test series in Pakistan for 17 years -- have another five sessions to force a result in the three-match series.
Opener Ben Duckett -- one of four century makers in England's mammoth 657-run first innings -- was caught at slip off the second ball of pacer Naseem Shah for a golden duck.
Fellow centurion Ollie Pope cracked two boundaries before hooking fast bowler Mohammad Ali into the hands of Naseem, scoring 15.
Earlier, debutant Jacks took all three wickets to fall after Pakistan resumed at 499-7 -- but not before the host's tail-enders scored freely on a much-maligned flat Rawalpindi Stadium pitch.
Agha Salman (53) and Zahid Mahmood (17) frustrated England for 50 minutes during their stubborn eighth-wicket stand of 57.