The Brazilians cruised through their Second preliminary round clash with Remo Stars 7-1 on aggregate, following a 5-1 away win and 2-0 victory at home on Sunday.
Nuno Santos netted his first Downs' goal and Peter Shalulile added a second at Loftus Versfeld for a one-sided victory.
Last season, Sundowns recorded a similar result in their CAF qualifier, with a 8-0 aggregate win over Mbabane Swallows before struggling in subsequent ties with AS FAR, Raja Casablanca and Maniema Union.
They ultimately made it to the final but lost to Egyptian side Pyramnds 3-2 over two legs.
The draw for this season's group stage takes place on November 3.
Cardoso said in the Citizen that his side need to be wary of all the teams in the group stage and not just the so called 'big-name' teams.
"Sometimes you think you'll play a team that doesn't have a [big] name but when you play them away, it becomes so difficult," said the head coach.
"I would like people to remember that last year, the worst team theoretically was Maniema Union and we played a draw in the first match at home and it made it difficult on what will happen throughout the competition, especially when we had AS FAR and Raja Casablanca in the group.
"You remember with me that with five minutes left against Maniema, we were losing 1-0 and we were out of the group stages but Peter Shalulile scored two goals and we went through. We played the decisive match at home to AS FAR, a draw which was enough for us to go through."
"I expect a draw that can be very tricky, as I see big teams that are powerful and are impactful," Cardoso added.
“There are also teams that don't have (big) names but they are tricky to play, especially away, so we need to take competition seriously. To play in the Champions League, you need to bring the level of your game to the maximum and (still) raise it.”
Marumo Gallants coach Alexandre Lafitte believes his side has what it takes to pull off another upset when they face Orlando Pirates in the Carling Knockout final at Peter Mokaba Stadium on December 6.
Miguel Cardoso says Mamelodi Sundowns need to build on their 1-0 midweek win over TS Galaxy to make up for a poor start to the Betway Premiership campaign.
Mamelodi Sundowns coach Miguel Cardoso has praised Sphelele Mkhulise's influence and professionalism, describing the midfielder as a player who represents the very identity of the club.
Mamelodi Sundowns maintained their lead at the top of the Betway Premiership, while there were also wins for Siwelele FC and Durban City in Wednesday night's domestic action.
