"We recently showed the players a film concerning events of 6 February, and you couldn't hear a pin drop," he told manutd.com.
"I know what players are usually like when they're called into the classroom, it's a bit of a giggle, a laugh, the usual carry on. But it was an absolutely fantastic atmosphere, so silent."
With a squad brought together from such diverse backgrounds and cultures, Sir Alex and his staff were keen to ensure that all the players were schooled on a massively important chapter in United's opulent history.
"Bobby Charlton did a piece on the club and what it was like for him and the players and friends he lost," revealed Sir Alex.
"Foreign lads like Anderson, Nani and Carlos Tevez may not know about Manchester United in the same way Ryan Giggs, Paul Scholes and Gary Neville do, but I think it was terrific to get that response: it was quite a solemn moment.
"And there is no need for us to continually repeat it to them; they will gradually learn about it, because it is indelibly printed in our history."