QPR are bottom of the table but have dragged themselves back into survival contention with consecutive league wins and are four points adrift of Villa who are hovering precariously one place above the relegation zone.
"It (Villa) is a massive club with a young team and the pressure of the home crowd can affect people's performances," Redknapp told reporters on Friday.
"We go into the game away from home and people wrote us off a few weeks go but we've put ourselves back in the picture and in there with half a chance, so the pressure isn't really on us.
"It's a big game for sure. It's a massive game for both teams. We're both in a real battle so it's going to have an important bearing on the league.
"It would certainly help either side if they could get a win. It would make a massive difference to how things look on Sunday morning in terms of the table."
QPR's position is precarious after club accounts published last week showed they were 89 million pounds ($133.97 million) in debt.
The figures did not include the last two transfer windows when QPR invested heavily in players, with Redknapp splashing 20 million pounds on forward Loic Remy and defender Christopher Samba in an effort to spark a revival.
Relegation remains a realistic prospect despite their recent upturn in fortunes that culminated in last weekend's 3-1 victory against Sunderland.
"The lads are in good spirits," Redknapp said. "It was a great result to come back from 1-0 down against Sunderland and get three goals. That's five in two matches now and that's good for us.
"We were difficult to beat before but now to be scoring goals is good for us." ($1 = 0.6643 British pounds)
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