JOIN USA rain-affected match appeared destined for a draw after England declared their first innings on 496 for five -- a lead of just 96 -- with only 51 overs left in yesterday's fifth and final day here at Sophia Gardens.
But what had seemed a moribund match was sparked into life by England fast bowler Chris Tremlett who, maintaining an accurate line and length at sharp pace ripped through the top order on his way to four for 40.
Off-spinner Graeme Swann (four for 16) followed up and Sri Lanka were bowled out inside 25 overs to go 1-0 down in this three-match series.
They do not have long to regroup before the second Test at Lord's on Friday and Dilshan said: "I am really calm, I can't be angry.
"It will be difficult to forget this Test match but we have to stick together as a team.
"We can regroup and come back for the Lord's Test in a positive mind and then we can play some good cricket there."
This was Sri Lanka's first Test outside the subcontinent since 2008 and this defeat, coming in the first match under interim coach and former Australia batsman Stuart Law, will confirm suspicions that while they remain a force in Asia, they are nothing like as effective away from familiar conditions.
Before this series began, it appeared bowling was Sri Lanka's biggest concern with star spinner Muttiah Muralitharan, slingshot seamer Lasith Malinga and left-armer Chaminda Vaas having all retired.
Sri Lanka then suffered the double misfortune of seeing pacemen Nuwan Pradeep (cruciate ligament) and Dilhara Fernando (knee soreness) both ruled out of playing in Cardiff through injury.
Pradeep has since had to return home but Sri Lanka remain optimistic Fernando will be fit to play at Lord's.
But even if Fernando returns, that will do nothing to dampen fears regarding a Sri Lanka top order who so spectacularly slumped in Cardiff on a pitch that, while lively, was no 'terror track'.
Three of Sri Lanka's batsmen -- Kumar Sangakkara, Thilan Samaraweera and Mahela Jaywardene -- came into this match each averaging over 50 in Tests.
Yet the trio managed just 29 runs between them yesterday, with Samaraweera playing on to Swann for nought.
"It's very difficult to explain, I can't believe we got out in just 25 overs with such a good batting line-up like we have," Dilshan said after seeing Sri Lanka bowled out for their lowest Test total in England, beating their 141 in Birmingham five years ago.
"Our batting line-up has guys like Mahela, Kumar, Thilan and myself.
"We are experienced players and we need to regroup as soon as possible and come back for the next Test on Friday."