The Brazilians are looking to make up from their exit from the CAF Champions League at the second qualifying round, with victory against Golden Arrows in the League Cup.
They already have the MTN8 cup in their trophy cabinet, having seen off Orlando Pirates in the 2026/27 final and are top of the Betway Premiership after 10 games.
Downs, meanwhile, beat Marumo Gallants 1-0 in the last 16 and are up against an Arrows side that saw off Chippa United 4-0.
Heading into the tie, the Tshwane side defeated Durban City 4-1 in the league as Arrows lost 1-0 to AmaZulu.
Speaking in the build-up to the game, Rayners admits that Sundowns won't have it easy against Mandla Ncikazi's Arrows.
"Knockout games are always difficult to play because you don't know what to expect from the other teams but as a team, we know how to win games like this, especially when it becomes difficult," Rayners said on IOL.
"We always have a lot of opportunities against them, but we just have to make sure we punish them as early as possible because once we do that, the game will open up and we know we'll win."
"I think their coach is a good coach especially when teams play against Sundowns, they know how to setup but we just need to do our job and work as hard as possible to win the game and get the result," added the Bafana Bafana attacker.
Ronwen Williams and Teboho Mokoena remain injury doubts for Mamelodi Sundowns head coach Miguel Cardoso ahead of the CAF Super Cup final clash against USM Alger at Loftus Versfeld on Sunday.
Mamelodi Sundowns head coach Miguel Cardoso praised his team for grinding out a 1-0 win in their Carling Knockout Cup quarter-finals clash with Golden Arrows on Tuesday.
Iqraam Rayners netted the only goal of the game as Mamelodi Sundowns booked their place in the semi-finals of the Carling Knockout Cup after beating Golden Arrows 1-0 at Loftus on Tuesday.
Rushine De Reuck has reflected on his time at Mamelodi Sundowns after scoring for Simba SC in their 3-2 Tanzanian Premier League comeback win over Namungo on Monday.
