"I played against Munster in a pre-season friendly (in Cork last September) and, although they were missing their World Cup players, the biggest thing is the physicality of the team, regardless of whether or not it's at full strength," said the South African scrum half.
"They shocked us a bit in that department and it was that physicality which led them to the win and is the main area of the game we will need to focus on for Sunday.
"But just being in the Heineken semi-finals for the first time is a great position to be in, especially as we were not tipped to be there.
"Munster have been there and done that but for us it's all new so we will be looking to the older guys to calm things down and bring their experience to the table in order to keep ourselves in check for the match," he added.
"But having lost Andy Farrell and Chris Jack through injuries, we have had to work very hard to make up for their absences. They are players who have been on the World stage and everyone knows how valuable that experience is as well as their individual talents.
"Having said that, there are guys who have stepped up and taken on the challenge. Hugh Vyvyan in particular has been outstanding and, having been without these guys for the quarter-final, which nobody thought we would win, we are ready to face the semi-final without them as well."
de Kock, the 10-times capped Springbok, was delighted with the performance Sarries put in in their 19-10 quarter-final win over the Ospreys.
"I think our performance against Ospreys was definitely one of our best of the season. We went into that game having been written off by most people - and quite rightly so given our performance against them the previous week in the EDF Energy Cup semis.
"If we had played the same way in the Heineken semi-final, we would have got hammered and you have to respect the guys for coming out and putting in the performance on the day, as they did for the Biarritz Olympique game in the pool stages where I think we put in another great performance.
"And the way we played against Ospreys is where we want to be as a team. But we then took five steps backwards the following weekend against Gloucester, so it is our consistency rather than our ability to pull off one-off performances which worries us," he admitted.
de Kock knows having Alan Gaffney, a former Munster coach, at the helm is a big plus for the Vicarage Road outfit as they face into what is sure to be a stern test against the Irishmen.
"Munster are a very physical side so we have to get it right in the contact area or it's going to be a very long afternoon on Sunday.
"Alan Gaffney's knowledge of Munster is clearly going to be massively important for us as he has a great deal of know-how and insight into how the side ticks.
"I know that Munster have changed a couple of personnel since he was there but their game focus and style of play hasn't changed much since he left.
"Having said that, although this will stand us in good stead, we still have to go out on the pitch and do the business."