Saracens won't focus on Carter
New Zealand World Cup-winner Carter has guided the Paris club to their first major European Final and is now just 80 minute away from completing a personal clean sweep of Rugby Union's leading international and club titles.
"It's a big, big, big mistake to think you're going to go and get Dan Carter," said McCall at English Premiership champions Saracens' training ground in St Albans, north of London, on Monday.
"Dan Carter's been doing this for a very long time. So we've got to make sure that his influence in the game isn't huge, isn't unbelievably significant.
"And if we can do that it means our pack have got on top in the scrum, in the line-out. It means we'll have put a little bit more pressure on him than he's experienced before.
"But if you run down his channel and think you're going to shake him up, you're not going to."
Machenaud's value in allowing Carter to play deeper and stay out of the way of opposition forwards was seen to good effect in Racing's 19-16 Champions Cup semifinal win over Leicester in Nottingham.
"Machenaud's unbelievably competitive, he gets his attack going," said McCall.
"He brings their big men into the game and someone we're going to have to watch like a hawk," the former Ireland centre added.
"He and Carter work very well together, and Dan Carter's an expert at picking his moment at when to involve himself, and usually it's a pretty good involvement.
"We've just got to make sure we're really alive to every time that he's going to get the ball, kick and try to put us under some pressure."
Saturday's match in Lyon will be Saracens' second appearance in European club Rugby Union's showpiece match following their 23-6 defeat by a star-studded Toulon side helmed by Jonny Wilkinson in Cardiff in 2014.
The London club are determined not to repeat their experience of two years ago when, in McCall's words they tried to "squeeze their day" by flying down to the Welsh capital on the morning of the game and then getting caught in the crush of spectators trying to get a train after a match at the Millennium Stadium.
As is the case now, Saracens were on course for a domestic and European double two years ago.
But the 2013/14 season was one of double disappointment for Saracens when, the week after losing to Toulon, they suffered an extra-time defeat by Northampton in the English Premiership Final.
"We made a big mistake two years ago: we tried to squeeze our day," said McCall, whose side now contains six members of the England squad that won this season's Six Nations with a grand slam - Alex Goode, Owen Farrell, Billy and Mako Vunipola, George Kruis and Maro Itoje.
"We flew down to Cardiff on the day of the match and struggled to get a train home after the match.
"So this time we're going to go and enjoy ourselves and take our time, and embrace the weekend properly."
He added: "That being said of course we want to be able to put our best foot forward.
"We weren't able to do that two years ago, maybe because we weren't good enough, maybe because we weren't experienced enough.
"But I think we're experienced enough now."
Agence France-Presse