Joe Root's hunger and consistency can help him become the top run-scorer in Test cricket, fellow Englishman Alastair Cook said after being surpassed by him as the country's most successful batsman in the format on Wednesday.

Root eclipsed Cook's tally of 12,472 runs when he reached 71 not out with an elegantly driven boundary on Day 3 of the first Test against Pakistan and the former captain celebrated with a wave to the dressing room.

He went on to score a century after lunch.

"Root would have known (he had broken the record). You just do, don't you? And what a shot to do it," Cook told the BBC.

"Probably for Root now, he's got bigger fish to fry.

"I don't know what his exact aim is, but he's not lost that hunger and desire to keep on scoring runs."

Cook said Root, who is now fifth in the all-time list of run-scorers, can set his sights on overhauling Indian maestro Tendulkar who is at the top with 15,921 runs.

"I can see Root overhauling Tendulkar's record. When I retired, I thought there was every chance that my record will be broken. I thought only the effects of captaincy and the hunger that takes out of you would stop him," Cook added.

"The fact that Ben Stokes has taken over the captaincy has helped Root... He's been lucky with injuries. All great players who played for a long time have been lucky with injuries.

"You just never know what's around the corner, but it has to be something like it that could stop him. But I don't see that happening for Root to lose that hunger and ability to keep driving himself forward for the next couple of years."

Root's effort also drew praise from England great Michael Atherton, who witnessed his feat in Multan.

"It's a remarkable achievement, he's been a remarkable player," Atherton said on Sky Sports.

"He's been so consistent over the years and he's done it in a way which is so pleasing on the eye... He's a nice lad, which adds another element to it.

"Sportsmen should be judged on sport but if you're a good lad with it, that's an extra notch too."

British Prime Minister Keir Starmer led the tributes from outside the cricket fraternity.

"A fantastic achievement from an outstanding cricketer who just gets better and better," Starmer said on X.