Pakistan made it two wins from two World Cup matches as batsmen Mohammad Rizwan and Abdullah Shafique hit centuries in a record run-chase to set up a six-wicket victory over Sri Lanka in Hyderabad on Tuesday.
Chasing a daunting 345 after Kusal Mendis and Sadeera Samarawickrama smashed tons to put Sri Lanka in a commanding position, the 1992 champions got over the line in 48.2 overs thanks to Rizwan's 131 not out and Abdullah's 113.
Ireland had held the previous record for the highest run chase in World Cups with 329 against England in 2011.
"Whenever you perform for your country and the performance is like that to win the match, it leaves you speechless," said player of the match Rizwan, who smashed eight fours and three sixes in his 121-ball knock.
"It was difficult and when you chase like that it's always special. In the dressing room after we bowled, every player had the belief that we were going to chase that."
It was also the first time in a World Cup match that four centuries had been hit and Mendis got the ball rolling with a blistering knock after being dropped on eight by Shaheen Shah Afridi and on 18 by Imam-ul-Haq.
He dominated Pakistan's bowlers earlier with 14 fours and six sixes to score 122 before Samarawickrama dropped anchor to make 108 as Sri Lanka posted 344-9 in 50 overs, although they were restricted at the end by Ali (4-71) and Haris Rauf (2-64).
Mendis reached his century in 65 balls -- the fastest by a Sri Lankan at the World Cup -- flicking pacer Hasan Ali for a six off his legs to eclipse former skipper Kumar Sangakkara, whose ton had come off 70 balls against England in 2015.
"Mendis is in form at the moment and is in another zone," Sri Lanka skipper Dasun Shanaka said as he counted the positives ahead of their clash with Australia next week. "It's his time in the tournament and there's more to come from him.
"Also, Sadeera has been playing very well in the recent past so really happy with the way those guys played, but in the end we should have finished a bit stronger than this.
"With the way the wicket behaved, we were 20-25 runs short."
Pakistan made a shaky start as Dilshan Madushanka (2-60) dismissed Imam and Babar Azam inside eight overs and Shafique was cautious early on before cutting loose to build a superb 176-run partnership with Rizwan.
Shafique, who replaced the out-of-form Fakhar Zaman, cracked 10 fours and three sixes and was primed to stay until the end on his World Cup debut but he fell to Matheesha Pathirana after a stunning catch by substitute Dushan Hemantha.
Rizwan was hit on his face and battled cramps after getting into the eighties but soldiered on for his third century, before guiding them home by hitting the winning runs.
"All credit to the boys, especially Shafique and Rizwan. The way Rizwan played, he built the partnership and put pressure on the Sri Lankans," said Pakistan skipper Babar, whose side meet arch-rivals India in Ahmedabad on Saturday.
"I'm very happy with Shafique and impressed with the way he is playing. It's his first World Cup so he's hungry to play. I saw in the nets he's in good nick so I decided to play him."