Captain Andrew Strauss said England's innings and 14 run-win over Sri Lanka in Cardiff "beggared belief" after a sensational final-session collapse.
Sri Lanka lost eight second-innings wickets after tea on a rain-affected final day of the first Test.
"We were not expecting this at the start of the day, it beggars belief to a certain extent," said Strauss.
"We were not expecting a huge amount, although we knew it was an awkward time for them to bat.
"It was one of those situations as a batsman you have nothing to gain and everything to lose.
"There was some really high-quality bowling at both ends which meant we were able to take wickets at both ends."
Over 15 hours of play were lost during the Test because of wet conditions.
For the fourth time in five days, the start of the day's play was delayed by persistent rain in the Welsh capital, with the first delivery bowled just after 1500 BST.
With England resuming on 491-5 overnight, Strauss declared after two overs when Ian Bell reached his 13th Test hundred, setting up an awkward few hours for Sri Lanka's batsmen to negotiate.
But even without pace spearhead James Anderson, missing because of a grade one side strain, Chris Tremlett and Stuart Broad produced a hostile opening spell, extracting movement and bounce on what had been a placid wicket for Sri Lankan seam duo Thisara Perera and Suranga Lakmal.
And the key dismissals of experienced pair Mahela Jayawardene and Kumar Sangakkara, with over 18,000 Test runs between them, after tea contributed to Sri Lanka's joint fourth lowest total in Test cricket in a humiliating defeat.
"I'm proud of the way we approached things this afternoon," a delighted Strauss told BBC Sport.
"We hit them hard with the new ball, got the early wickets and built more momentum as the innings went on.
"For Broad and Tremlett to bowl with ferocity was a great effort. The general feeling of intensity was excellent too."
His opposite number Tillakaratne Dilshan admitted Sri Lanka's defeat was "difficult to explain".
"I can't believe we got out in just 25 overs with such a good batting line-up like we have. We lost the match because we batted really badly," said the Sri Lanka skipper.
"We knew we would be batting for at least 45 or 50 overs. We knew in the morning that they would declare, everyone knew that after Bell's hundred they would declare, but I cannot explain what happened.
"Our batting line-up has guys like Mahela, Kumar, Thilan [Samaraweera] and myself, we are experienced players and we need to regroup as soon as possible and come back for the next Test on Friday."
Dilshan also had no complaints about the Cardiff pitch.
"It was a very good wicket with a little bit of turn and a bit of bounce," he added.
"In the last two days it was good for batting, but we didn't bat well, that was the main issue, but it was really good for Test cricket."
Man-of-the-match Jonathan Trott's second Test double hundred had created the foundations for England's seamers to wreak havoc alongside Graeme Swann, ripping through Sri Lanka's brittle batting line-up in the late Cardiff sunshine.
"Trott has been a real rock for us over the past 18 months," said Strauss.
"It is the incredible calmness with which he goes about his business, he makes everyone comfortable in the dressing room and we know he is not going to give his wicket away cheaply."
England are set to announce their squad for the second Test at Lord's, which starts on Friday, at 0900 BST on Tuesday with Anderson set to miss out as he recovers from his side injury.
Steven Finn remains favourite to replace the Lancastrian but Ajmal Shahzad, Graham Onions and Jade Dernbach will all be vying for contention when national selector Geoff Miller convenes his panel alongside fellow selectors Ashley Giles and James Whitaker.
"I thought James bowled outstandingly well in the first innings, right back to how he bowled in Australia, very good control and probing," added Strauss.
"But we will have a conversation about who to replace him tonight. We had some good bowling reserves so whoever comes in will do a good job."
Listen to Jonathan Agnew and Geoff Boycott's review of each day's play on the TMS Podcast page