Pakistan took a 20-run lead after rallying to post 538 all out in its first innings against England in the third Test on Sunday -- a spell that included a record 363-run third-wicket stand.
Pakistan recovered from 451-6 to go past England's first innings total of 515 on the third day at Headingley.
England reached 3-0 in the first two overs of its second innings before stumps, with Marcus Trescothick on 0 and Andrew Strauss on 3.
"It looks like 50-50," Pakistan vice-captain Younis Khan said. "If we make some wickets early morning, it could be 70-30 [for Pakistan]."
England allrounder Paul Collingwood said England would play to win despite only needing a draw to win a home series against Pakistan for the first time in six attempts since 1982. That also came at Headingley.
"We'll go out there and judge how the pitch is playing and go and play it as if it's the first innings," Collingwood said. "Then we can reassess as the day goes on."
Khan and Mohammad Yousuf had taken advantage of the flat Headingley wicket and humid conditions to build a 363-run third-wicket stand -- the fifth-highest partnership of all time against England.
"The key is all the time that we take quick singles and we are talking and laughing," Khan said.
Yousuf fell eight runs short of his fifth Test double century when he was caught behind by Chris Read off the bowling of Steve Harmison.
Khan, went for 173 -- his best ever score against England -- after being run out by Sajid Mahmood.
Pakistan resistance faltered as England took three wickets in 10 balls as the tourists went from 399-2 to 451-6 in one session.
Khan's replacement, Faisal Iqbal, lasted one ball before being trapped lbw to become Collingwood's first Test wicket -- something that had taken him 64 overs to achieve since he made his Test debut in December 2003.
Four runs later, captain Inzamam-ul-Haq was dismissed for 26 after falling over his own wicket off the bowling of Monty Panesar on the last ball before tea.
"Sometimes you have to hold up your hands when the opposition batsman play well," Collingwood said.
"We didn't think the game was running away from us, we just knew we had to keep going and once we got the breakthrough, put the pressure on the new batsman," he said.