Kumar Sangakkara smashed his fastest ODI century off just 70 balls to help Sri Lanka thrash England by nine wickets in their World Cup 2015 Group A encounter in Wellington on Sunday.

England's captain Eoin Morgan won the toss and elected to bat first. His openers Moeen Ali and Ian Bell set-up a 62-run opening stand, before Ali fell in the tenth over.

Gary Ballance was the next to depart two-overs later. His exit brought Joe Root to the fore. Root and Bell added 30 for the fourth wicket, before Bell departed.

Root stood tall while wicket fell at the other end. Sri Lanka missed their opportunity to dislodge him, when he was just two, when Mahela Jayawardene dropped him in the slips.

He made them pay and became the youngest England century-maker in a World Cup. Root's innings helped his side score a respectable 309.

It took England 19 overs to find their first break-through. They dislodged Tillakaratne Dilshan for a well-made 44.

England tried to capitalize on the Dilshan's departure but Lahiru Thirimanne and Sangakkara dropped anchor and refused to hand over the initiative.

The pair added 212 for the second wicket in 28.2 overs. Sangakkara raced to his hundred from 70 balls - his fastest one-day hundred - to follow his 76-ball 105 against Bangladesh at the MCG.

He shredded England's attack with piercing drives, dismissive pulls and the occasional touch of deftness. His partner too put on an impressive display and hit 13 fours and two sixes to reach his fourth ODI ton.

England's bowlers had no answer to Sri Lanka's stoic-display with the bat. The Thirimanne-Sangakkara combine took their side home in 47.2 overs.

"Credit should go to the openers. They had a great start. Thiri batted out of his skin," Sangakkara said. "We were getting 5.5-6 an over throughout. It was just a case of batting long. It is always imposing when someone scores 300. Joe Root batted beautifully, but then again there are days like this. Getting old. Quite quickly. Still enjoying the game [About retiring after the Cup]. Thiri has batted from No. 1 to No. 9 for us. To watch him get that hundred was quite special."