Roy Hodgson has admitted his concern ahead of England's crucial World Cup qualifier with Poland, saying he anticipates a sleepless night before Tuesday's match at London's Wembley Stadium.
Friday's 4-1 home win over Montenegro means that if England beat Poland they will remain top of European zone Group H and qualify for next year's World Cup finals in Brazil.
But with group rivals Ukraine expected to beat San Marino, anything less than three points is likely to condemn Hodgson's side to a two-legged play-off.
Poland will arrive at Wembley knowing their own chances of World Cup qualification ended with last week's defeat by Ukraine.
However, Hodgson rejected suggestions that Poland had 'nothing to play for' at Wembley ahead of arguably the most high-profile match of his long managerial career.
'Anyone in football is a worrier'
"I'm a worrier. I think anyone who works in football is a worrier," Hodgson told reporters at England's hotel in Watford, north of London, on Monday.
"It won't be my best night's sleep because at the moment all of my waking thoughts are around England versus Poland.
"On the other hand, I have great faith and trust in the players. I don't think I can be putting a stronger bunch of players, a more confident bunch of players, onto the field.
"But football is not a science. If it was a science and based on logic and science, I think we would be 99 percent there.
"But it's not, it's a game and things can happen in games that you don't really want to happen and that's what makes you worried.
"It's not that you are worried the team is not capable, it's just that you are worried something untoward might happen."
The game has revived memories of the meeting between the two sides 40 years ago when a 1-1 draw at Wembley saw Poland qualify for the 1974 World Cup at England's expense.
Since then England have dominated this fixture but Hodgson said previous results would be no guide to the outcome of Tuesday's match.
"History's important when it comes to not making political mistakes but I don't think it has any relevance in sport whatsoever.
"Every game's a new game and each Poland team that's played England has been a very different team so, as far as we're concerned, we'll do our job against the Poland we will face."
Hodgson will be forced to make one change from the side that beat Montenegro with right back Kyle Walker suspended.
The manager refused to be drawn on Walker's likely replacement with Manchester United pair Phil Jones and Chris Smalling both in contention.
Hodgson did concede he wanted to keep changes to a minimum but revealed Andros Townsend -- man of the match on his England debut on Friday -- was carrying an injury.
"He took a knock against Montenegro so we will still monitor that but we are very hopeful that he will be able to play," Hodgson explained.
The Football Association's decision to make 18,000 tickets available to visiting fans has been criticised but while Hodgson believes the backing could lift Poland, he claimed the authorities had little choice.
"There are a lot of Polish people living in this country and I understand the FA were virtually forced into this decision to let the Polish FA have the tickets, because otherwise there would be safety problems with the infiltration of Polish fans amongs the England fans," he said.
"As far as I am concerned, our players are pretty used to playing in games where the opponents have their support as well and I also think the 65,000 or 70,000 (England fans) versus 20,000 is a pretty good margin for us."
Meanwhile Hodgson said he'd no plans to change his own low-key approach in the final moments before kick-off.
"I don't thing I do too many Churchillian speeches, do I?", Hodgson asked Steven Gerrard, the England captain.
"No," was the midfielder's deadpan reply.