Curtis Davies fears Aston Villa's trip to Old Trafford has been made harder by Manchester United losing successive games.
Villa head to the Premier League leaders on Sunday, live on Sky Sports 1 & HD1, in need of the points to boost their flagging UEFA Champions League aspirations.
Martin O'Neill's side have failed to win in their last five league games and Davies is aware of the challenge facing Villa at the weekend.
"This weekend's game is obviously going to be a very tough test for us," said Davies. "I actually think it's made even harder by the fact that United have lost their last two games.
"They will be looking to win to keep Liverpool at arm's length at the top of the table.
"They have three suspensions to key players - Wayne Rooney, Nemanja Vidic and Paul Scholes - but they're able to bring in international replacements in all those positions.
"This just shows the depth of their squad."
Davies knows Villa have to bounce back from their own 5-0 hammering by Liverpool and has urged his team-mates to be positive against United.
The centre-half added: "We have to be positive. We certainly can't feel too sorry for ourselves after the defeat at Anfield. We just have to pick ourselves up for another big game.
"We have to stay positive about our top-four chances too. If we don't we might as well give up now.
"We have had a bad March, but we have to stay mentally strong and pick up as many wins as possible. We can't worry what Arsenal or Everton are doing."