Ben Duckett hailed "extremely humble" Joe Root after watching his team-mate become England's all-time leading Test run-scorer on day three against Pakistan.

Root needed 39 entering Wednesday's play in Multan to break Alastair Cook's record, and he surpassed that target with ease, ending the day unbeaten on 176 alongside Harry Brook.

In his 147th Test outing, Root drilled Aamir Jamal's delivery in the blistering heat to overtake Cook's previous record of 12,472 as England closed to within 64 runs of Pakistan on 492-3.

Duckett partnered Root for the historic moment and led the tributes at the end of play.

"He is extremely humble," Duckett, who recovered from a broken thumb to make 84, told Test Match Special. "It doesn't feel like you're sat around greatness.

"He's just hungry for runs every time he goes out bat for England. It's incredible to be in the same dressing room as him and long may it continue."

Root now has 12,578 runs in 146 matches, which has seen him bat in 268 innings in total, with his tally consisting of 35 centuries, 1,355 fours and 44 sixes.

The 33-year-old is up to fifth on the all-time list of run scorers across all nations, with only Rahul Dravid (13,288), Jacques Kallis (13,289), Ricky Ponting (13,378) and Sachin Tendulkar (15,921) ahead of him.

England batting coach Marcus Trescothick added to Sky Sports: "We're lucky enough to sit and watch history being made as a man goes on to be the leading run scorer in his country.

"The way he goes about it, the work he puts in and continues to strive for greatness all the time. He's been superb and think will continue to be superb for a number of years yet."

Amid all the fanfare for Root, England will enter day four looking to create some history of their own.

The tourists have never conceded as many as Pakistan's 556 and gone on to take a first-innings lead.

"The pitch is not doing a great deal at the moment and to be in a position where we can say we can get [a lead of] 150-200 is an incredible effort," Duckett added.

"The morning session will be important and if we can limit the damage, we can kick on in the afternoon."