After choosing to bat, England were on the back foot when Ben Duckett (7) and Rehan Ahmed (24) fell inside the opening 11 overs.

But Root and Jacob Bethell steadied the innings with a controlled 126-run stand for the third wicket before Bethell’s assured 65 ended when Jeffrey Vandersay struck.

Root then found a perfect partner in captain Brook, whose explosive innings shifted the momentum decisively.

Brook plundered an ODI career-best 136 off 66 balls, hammering 11 fours and nine sixes in a blistering display that transformed England’s innings.

Root anchored the other end with a composed unbeaten 111 off 108 deliveries, and together they added an unbeaten 191 from 113 balls to lift England to a commanding 357-3.

Sri Lanka began their chase with intent.

Kamil Mishara contributed 22, and Pathum Nissanka hammered five fours and three sixes in a 24-ball fifty before his dismissal by Jamie Overton checked the momentum.

Captain Charith Asalanka (13) and Janith Liyanage (22) fell cheaply as England applied sustained pressure with disciplined bowling.

The hosts slipped to 202-6 in the 32nd over and, although Pavan Rathnayake (121) kept Sri Lanka afloat with a composed maiden ODI century, wickets continued to fall around him.

Rathnayake’s resistance ended when Sam Curran breached his defence with a full delivery that knocked back his leg stump, and Sri Lanka were bowled out for 304.

“It was an awesome effort from everybody involved,” said Player of the Match Brook. “Rooty’s just exceptional. To have him in the side helps every day.

“It was a lot better pitch than we were expecting. It still had a part to play and just glad that we got a good score and we managed to defend it.”

Sri Lanka had won the first ODI by 19 runs before England levelled the series with a five-wicket victory.

“It was tough to contain them (Root and Brook),” Asalanka said.

“I thought the ball might turn on this surface but when it’s not turning it’s hard to bowl in the last 10 overs with spinners.

“I think the Twenty20 series is the most important series before the T20 World Cup. We want to do the basic things right before an important World Cup.”

The three-match T20 series starts on Friday.