England, Pakistan in victory race as bold declaration transforms Pindi Test
Brook's high-tempo fifty and early breakthroughs keep all results possible for day five
Pakistan 579 (Babar 136, Imam 121, Shafique 114) and 80 for 2 (Imam-ul-Haq 43*, Shakeel 24*) need 263 runs to beat England 657 and 264 for 7 dec (Brook 87, Root 73, Crawley 50)
Another fearless performance by newcomer Harry Brook, a calculated declaration and a short-ball barrage that had Pakistan reeling initially in pursuit of a lofty 343 runs for victory: Bazball was on a Rawalpindi rampage on the penultimate day of this first Test.
When England's fresh, aggressive approach to Tests was still in its infancy during their home summer and they came a cropper against South Africa at Lord's, new head coach Brendon McCullum's message was simple and effective, along the lines of: if you think you've pushed hard enough, push some more.
His charges have wholeheartedly embraced the message, positioning themselves to claim the remaining eight wickets they need - possibly seven depending on how Azhar Ali pulls up overnight from a finger injury - on a pitch that has proven to be a batting paradise.
Pakistan are not out of the contest with Imam-ul-Haq, who made 121 in the first innings, steadying the hosts from 25 for 2 and unbeaten on 43 at stumps, and Saud Shakeel not out 24, needing another 263 runs.
An enthralling day's play began with Test debutant Will Jacks completing a six-wicket haul on debut after the hosts had put up an hour-and-a-half's worth of resistance, thanks to Agha Salman's fifty which contained England's first-innings lead to 78 runs.
But the tourists then stretched that to 342 in 35.5 overs of high-tempo batting in their second innings, Brook stealing the show among England's three half-centurions with a sublime display of strokeplay and timing.
Then Pakistan succumbed to England's short-ball tactics which, in the space of nine eventful deliveries, accounted for opener Abdullah Shafique and captain Babar Azam , either side of Azhar retiring hurt.
Pakistan were 20 without loss after four overs in their second innings, sedate in the bizarre context of the feverish run-rates so far but a positive opening gambit in its own right, as both men traded the threat of England's bouncers with the scoring opportunities they offered
But then Ollie Robinson removed Shafique, pulling to Brook at deep square leg before striking Azhar a heavy blow on the tip of his right index finger, which sent him back to the dressing-room for treatment while on nought, and brought Babar to the crease, to the home crowd's delight.
Babar was the leading scorer among three Pakistan centurions - and seven in total - for the match with his first-innings 136. but he managed just four before feathering a Ben Stokes bouncer to wicketkeeper Ollie Pope as a hush fell over the stands.
England could have had another wicket late in the evening when substitute fielder Keaton Jennings put down a chance at short leg off Shakeel, then on 22, from the bowling of Jack Leach.
Stokes had declared during the tea break after Brook, Joe Root and Zak Crawley all reached fifties in the middle session.
England were 46 for 2 at lunch after Ben Duckett followed his first-innings ton with a first-ball duck and Pope fell for 15.
But Brook upstaged all others for a second time in just his second Test. Having top-scored in England's first innings with a rapid 153 off just 116 balls, he threatened to post another quickfire century with a boundary-laden 87 off 65 balls. Three times Brook powered Zahid Mahmood over the rope for six, his big shots looking effortless much of the time, before he was bowled by Naseem Shah on the stroke of tea going for one swing too many.
Crawley added another fifty to his first-innings 122, but no sooner had he brought up his latest milestone in 47 balls, he was caught behind off a Mohammad Ali short ball with Pakistan overturning umpire Ahsan Raza's not-out decision when replays showed that the ball had kissed the glove on the way through to Mohammad Rizwan.
Root reached the same milestone off 48 deliveries, crashing Naseem's fuller ball through mid-off to the boundary as England kept the tempo high. Then, in an audacious move, Root switched to batting left-handed for the first ball of legspinner Mahmood's first over after drinks.
He produced two sweeps, the second of which was put down by Naseem at midwicket then, switching back to right-handed, Root reverse-swept the next ball he faced through backward point for four. Root eventually fell sweeping too, top-edging a Zahid delivery which was going wide down the leg side to Imam at short backward square. Stokes followed for a duck off the third ball he faced, chasing a Zahid ball outside off and bobbing a catch to Shakeel at cover.
Jacks staged a doughty cameo of 24 off 13 balls, including three sixes, before he holed out to long-off, bringing like-minded heavy-hitter Liam Livingstone to the crease after spending much of the Pakistan innings off the field with a knee injury. Livingstone remained unbeaten on 7 at the declaration.
Jacks, called up as a late replacement for Ben Foakes who was struck down by illness on the eve of the match, ended up bowling more than he ever would have imagined with fellow debutant and part-time spinner Livingstone out of action. Jacks sent down down 40.3 overs - second behind only frontline spinner Leach's 49 - and walked away with 6 for 161.
Jacks, who came into this match with just 21 first-class wickets, began the day with three more already to his name - including that of Babar - and, after the hosts resumed on 499 for 7, he took care of the rest.
Salman brought up his second Test fifty with a well-placed chip off Leach over the covers which raced to the boundary, but fell a short time later, edging Jacks to Crawley at slip.
The dismissal brought in Test debutant Haris Rauf, who was cleared to bat but not bowl in England's second innings after suffering a thigh strain from rolling over the ball while fielding on the first day. He was Pakistan's last man out, chasing a wider Jacks delivery and edging to Root, who took a strong catch reaching overhead at slip.
Valkerie Baynes is a general editor at ESPNcricinfo