The Angolan Girabola side held their Betway Premiership counterparts to a goalless draw in their second qualifying round first leg clash at Estadio Nacional da Tundavala last weekend.
Sundowns needed a win at Loftus Versfeld on Friday to progress in the competition, but after taking an 11th minute lead through Tashreeq Matthews, a 49th minute strike from experienced Angolan internatinal Mabululu secured Wiliete the win on away goals.
"Mabululu is an experienced player, he knows African football, more than African football, international football because he is a player for the national team and he played abroad for the last couple of years," the coach said on iDiski Times.
"He's really helped his teammates. This second half we had to change him, though, because of what happened. This boy we introduced in the match was from the youth team, it was the first time he played at this level."
While Mabululu took the plaudits, Bianchi also lauded Gilberto, who previously spent time in South Africa with Orlando Pirates.
"So this kind of players, these calibre of players as Mabululu and Gibela, they give confidence and help the young players of the team," added the head coach.
Orlando Pirates head coach Abdeslam Ouaddou has challenged his players to believe they can end the club's 31-year wait for a second CAF Champions League title after securing their place in the group stages.
Mamelodi Sundowns coach Miguel Cardoso has admitted that his team's mistakes and failure to manage their emotions proved costly as they suffered a shock elimination from the CAF Champions League.
Orlando Pirates breezed into the CAF Champions League group stage after a dominant 4-0 victory over Namibian side African Stars at the Orlando Stadium to secure a 5-0 aggregate victory.
Mamelodi Sundowns have been eliminated from the CAF Champions League by Angolan Girabola league leaders Wiliete SC on away goals.
