Joe Root is targeting "many more runs" after overtaking Alastair Cook as England's all-time leading Test run-scorer.

The 33-year-old surpassed Cook's previous high of 12,472 on day three of the first Test against Pakistan on Wednesday.

Root reached the mark by piling on 71 runs in the blistering Multan heat and reached 176 not out at the end of play with England 492-3.

"I'm obviously proud but still feel there is plenty more left to do, and many more runs left to get," Root is quoted as saying by BBC Sport.

"More than anything, the way we played as a team is what stands out - we've got ourselves back in a really good position."

Root's 12,578 runs consist of 35 centuries, 1,355 fours and 44 sixes, coming across 146 matches.

He is now 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.

And with time still on his side age-wise, Cook has backed the man who took his England record to overtake each of those legendary names.

"I would be betting on Root to do it," Cook told Test Match Special. "I don't see Root losing that hunger and ability to keep driving himself forward for the next couple of years.

"He's just this consistent run-scoring machine. There are other geniuses who can play genius innings, but Root is a genius with consistency."

England have never conceded as many as Pakistan's 556 and gone on to take a first-innings lead, but they trail by just 64 runs heading into day four.

"We've still got an opportunity to win the game, which is really exciting," Root added. "Hopefully we can kick on tomorrow."