The Brazilians return to the continental showpiece still hurting from last season's 3-2 aggregate defeat to Pyramids - a result that denied them a second African crown.
Under Miguel Cardoso, Sundowns have struggled to hit their usual heights this season, falling short in domestic cup competitions and looking unlikely to retain their Betway Premiership title. As a result, the Champions League has taken on added significance.
Sundowns now face Moroccan heavyweights ASFAR in a two-legged final, starting with the first leg in Pretoria on Sunday before the decisive return match in Morocco next week.
For Modiba, the key lies in correcting the costly errors from last year's final, particularly at home.
"We conceded at home in the first leg last season, and that made things difficult for us," he told the media ahead of the game.
"We know how important it is to keep things tight at the back this time around and make sure we give ourselves a strong advantage going into the second leg."
Having last lifted the trophy under Pitso Mosimane in 2016, Sundowns are desperate to add a second star - and salvage what has otherwise been an underwhelming season.
However, Modiba was quick to caution against complacency, highlighting ASFAR's hunger as first-time finalists.
"They will be just as motivated as we are. For them, it's a big opportunity, and for us, it's about making things right," he added.
With pressure mounting and expectations high, Sundowns know anything less than continental success will leave their season falling short.
Former Kaizer Chiefs head coach Ernst Middendorp has weighed in on the ongoing title race debate, suggesting that fixture scheduling may have handed Orlando Pirates an edge over Mamelodi Sundowns.
Mamelodi Sundowns host AS FAR in the first leg of the CAF Champions League final at Loftus Versfeld on Sunday, with both sides chasing a second continental title in a tightly poised showdown.
Mohau Nkota has opened up on the heartbreak Orlando Pirates endured in last season's CAF Champions League semi-final defeat, describing the missed opportunity as the closest he has come to fulfilling his "biggest dream."
TS Galaxy interim coach Bernard Parker has suggested that Mamelodi Sundowns' response to defeat may reflect mentality rather than fatigue, following their Betway Premiership clash earlier this week.
