Powell will be without suspended Arsenal striker Kelly Smith
England can put themselves within touching distance of qualification for the Women's Euro 2009 by beating the Czech Republic on Thursday.
Victory would take Hope Powell's team, the only Group One side with a 100% record, eight points clear at the top of the pool with three matches left.
The Czechs have a game in hand and their own record was spoilt only by a 2-2 draw with Spain in October.
England will be without Arsenal's Kelly Smith, who is suspended.
Any points dropped on Thursday could be the difference between qualifying or not
Smith is serving a one-match ban after collecting her second yellow card of the qualifying campaign in the 2-0 win against Northern Ireland a fortnight ago.
Smith is undoubtedly England's key player, but Powell said: "We've functioned without Kelly before, as we did in an 11-match unbeaten run in the build-up to Euro 2005.
"She was injured at that time and now she's suspended, but it's not about one player and, like before, we just have to get on with it.
"Someone else will get the chance to make their mark in what's going to be our toughest group match so far and our last home fixture.
"We finish off with three tough away games, including the Czech Republic, so any points dropped on Thursday could be the difference between qualifying or not.
"That means we will have to be totally focused and right on our game, because the Czechs are a decent side who could be dangerous."
Against the Czechs, who we see as our strongest rivals for qualification, we'll have to be far more clinical
Replacing Smith with either her club colleague Lianne Sanderson or Chelsea's Eni Aluko is likely to be the only change Powell will make to the side that beat Northern Ireland.
Her players will go into the match as newly enrolled associate members of the Professional Footballers Association, a move welcomed by captain Faye White.
"Although we're not full time pros, we are trying to be as professional as we can in every way and I'm sure the PFA will be able to help us in that respect," said White.
"As well as playing issues they will also provide us with support on managing our lifestyles, and I think their influence will give the women's game a real boost."
Arsenal defender White will be aiming to boost England's Euro hopes on Thursday, when Powell's team will have to be sharper up front than in Northern Ireland.
A host of chances went begging and White admitted: "We only scraped the win when it should have been far more comfortable.
"So against the Czechs, who we see as our strongest rivals for qualification, we'll have to be far more clinical."
England squad: Chamberlain (Chelsea), Telford (Leeds United), A. Scott (Arsenal), Unitt (Everton), Asante (Arsenal), Phillip (Arsenal), White (Arsenal), Stoney (Chelsea), Bassett (Birmingham City), Johnson (Everton), Westwood (Everton), Williams (Everton), J. Scott (Everton), Yankey (Arsenal), Carney (Arsenal), S. Smith (Leeds United), Aluko (Chelsea), Sanderson (Arsenal), Handley (Everton).