Sir Alex Ferguson fears the emotion of Manchester United's visit to Liverpool on Sunday could have a negative effect on his players.
The game will be the first for Liverpool at Anfield since the damning findings on the Hillsborough tragedy were announced by an independent panel last week.
Liverpool intend to mark the match with a number of significant gestures, including the formation a mosaic across three sides of the stadium.
Ferguson has already appealed for calm from United fans in what is certain to be a tense atmosphere.
And having gone through something very similar four years ago, on the 50th anniversary of the Munich air disaster, the Red Devils boss accepts it may have a hidden impact.
"It's a possibility, I don't deny that," said Ferguson.
"Human nature can be that way. When we played Manchester City for the 50th anniversary of Munich the place was so flat in the dressing room before the game. I even felt it myself.
"We just couldn't perform and were glad to get it out the way.
"It was such an emotional day for us and it could be that way on Sunday."
Having twice appealed for United's supporters to behave themselves, Ferguson opted not to deliver another plea, believing it would be pointless under the circumstances.
Instead, he wants the match to be played in the correct spirit, which will surely involve a pre-game handshake between Luis Suarez and Patrice Evra should both play.
"I don't think we should get into that now," he said.
"We should let the players get on with it. There is enough pressure on them.
"Liverpool have done their bit. We've done our bit.
"We've given a lot of messages so let the game go on."
If the significance of the occasion cannot be understated, neither can the need for points.
Liverpool are yet to win since Brendan Rodgers' arrival and hover precariously over the relegation zone.
United have stabilised their campaign with three successive victories since an opening weekend loss at Everton, but they have failed to win any of their last five matches at Anfield - their worst return for two decades.
"It's similar to when I came down here," said Ferguson.
"We could beat Liverpool but we couldn't win the league.
"The motivation leans on the side of Liverpool, particularly at Anfield. The crowd get behind them and they make it a real competition in terms of challenges and tackles.
"We know that will happen on Sunday.
"Last season we handled them much better. It was 1-1 in the league and nothing between the teams, then we threw away the FA Cup tie.
"We were by the far better team that day. If we get that performance on Sunday we will be okay."
Reds boss Rodgers has built an impressive reputation through his time as a coach at Chelsea and eye-catching managerial stints at Watford and Swansea.
Yet some are already starting to question whether the 39-year-old is the right man to occupy such a challenging role.
It reminds Ferguson of the position Andre Villas-Boas found himself in at Chelsea. And that did not end well for the Portuguese.
"Any young manager needs time but in the modern world you don't get a lot of that," said Ferguson.
"Look at Villas-Boas at Chelsea last season. He was a young man who lasted about seven months.
"We're in an age where patience is not a realistic thing. It's just not there."
Ferguson accepts times have changed from his arrival at Old Trafford, where he was into his fourth year before he finally managed to secure some silverware.
But the key to success remains the same. You have to win.
"The only route for any manager is success," he said.
"It's a results industry so winning matches is important.
"It's a different game from when I started. There was less pressure.
"The world has changed. The press has changed. But I always felt I needed to win games.
"That's what you're in it for. It doesn't matter whether you're managing Port Vale, Liverpool or Manchester United, you have to get results."