Mahela Jayawardene's team have been earmarked as potential semi-finalists with Australia, New Zealand and South Africa, meaning the match is almost a must-win for England if they are to have a good chance of finishing up in the top four.
The Sri Lankans have looked far more impressive than England so far, dispatching India in the group stage and taking apart hosts West Indies in their last Super Eights match in Guyana.
In between they lost by one-wicket to South Africa but fought back well with paceman Lasith Malinga becoming the first international cricketer to take four wickets in four balls.
Andrew Strauss was England captain for last June and July's home humiliation to Sri Lanka when Vaughan and Andrew Flintoff were injured, and ironically Strauss may return to face his tormentors on Wednesday having been dropped due to poor form.
England's top order have failed to fire and have not given a platform for Paul Collingwood and big-hitters Kevin Pietersen and Flintoff to hoist the side to a mammoth score.
"Wednesday is a huge game," Pietersen told reporters. "Our stats are not good against them in the past, especially the last 12 months, so we've got to turn things around.
"We need two points this week, minimum."
Strauss may come in for Ed Joyce, who hit two fifties in the group stage wins over Canada and Kenya but also bagged nought and one against New Zealand and Ireland.
Ian Bell has also flopped and could be sacrificed for Strauss, who could even play as a seventh batsman if England decide to omit all-rounder Ravi Bopara, who did not bowl in Friday's win over Ireland.
Occasional off-spinner Vaughan threw down nine excellent overs against Ireland to hand England fresh bowling options but a seventh batsman is probably a luxury they can not afford with pacemen James Anderson and Sajid Mahmood so inconsistent.
Flintoff has shaken off a twisted ankle while Sri Lanka's only selection issue appears to be whether to play all-rounder Farveez Maharoof or fast bowler Dilhara Fernando.
Eng use sidearm throws to combat Malinga: England have been throwing sidearm deliveries at their batsmen in the nets to prepare them for facing Sri Lanka fast bowler Lasith Malinga on Wednesday.
Malinga, who became the first international cricketer to take four wickets in four balls in the defeat by South Africa, has an unusually low, slingy action that generates prodigious swing.
"We've tried our best to emulate the trajectory of Malinga and the angle that he comes and the height but it is quite difficult to get the pace," England captain Michael Vaughan told reporters on Tuesday.
"So it is a bit of the unknown on Wednesday. The guys playing against him in the test series last year did okay. He has had one decent game in the tournament when he got four in four balls but he is also going for runs as well."
However, he was less sure that a batsman could ever properly prepare for facing mercurial Sri Lanka off-spinner Muttiah Muralitharan.
"It's very hard to emulate Muralitharan in the nets."
Lanka upbeat ahead of England tie: Meanwhile Lanka captain Jayawardene has said that while memories of a 5-0 thrashing of England will not be an issue for his side come Wednesday's clash, they could be for their opponents.
Jayawardene, who said that series had been the launch-pad for a run of form that has seen Sri Lanka tipped to repeat their 1996 World Cup triumph here, said he didn't expect last year's series to have too much of a bearing now.
"It depends if England is thinking about it," Jayawardene remarked.
"For us it's not an issue because we are playing in different situations, different tournament, different conditions and probably different personnel as well. Things have changed since we played England."
Sri Lanka enjoyed a crushing 113-run victory against hosts West Indies in Guyana on Sunday and Jayawardene, who scored a morale-boosting 82 in that match, said: "The mood is pretty good. The way we played against West Indies was very satisfying.
Jayasuriya, who briefly retired from Test cricket last year, looked near his best during his 115 against West Indies and Jayawardene was delighted by the form of the 37-year-old left-hander, whose century was his 25th at this level.
"He's been brilliant. He's working harder, he's enjoying his cricket and he played some really good innings, not just the one you saw against the West Indies. He keeps going, that's the character of the guy."
England: Michael Vaughan (capt), James Anderson, Ian Bell, Ravi Bopara, Paul Collingwood, James Dalrymple, Andrew Flintoff, Ed Joyce, Jon Lewis, Sajid Mahmood, Paul Nixon (wk), Monty Panesar, Kevin Pietersen, Liam Plunkett and Andrew Strauss. Coach: Duncun Fletcher.
Sri Lanka: Mahela Jayawardene (capt), Kumar Sangakkara (wk), Sanath Jayasuriya, Upul Tharanga, Marvan Atapattu, Tillakaratne Dilshan, Russel Arnold, Chamara Silva, Chaminda Vaas, Farveez Maharoof, Lasith Malinga, Dilhara Fernando, Nuwan Kulasekara, Muttiah Muralitharan and Malinga Bandara. Coach: Tom Moody.