The 'Crows' from southern mining city Lubumbashi took a two-goal advantage over Simba of Tanzania to Dar es Salaam where leading scorer Dioko Kaluyituka bagged a brace in a 3-2 victory Sunday.
A boast of Zambia-born Simba coach Patrick Phiri that his team were capable of beating any African rival did not translate to reality with an early goal from Given Singuluma for Mazembe setting the tone.
Shija Mkina equalised on 58 minutes and an exchange of goals from Kaluyituka and Mbwana Samata left the teams level midway through the second half before the Congolese struck the match-winner.
Mazembe, who stunned Brazilian champions Internacional in Abu Dhabi last December before succumbing to Inter Milan in the final, will face Wydad Casablanca of Morocco this month with a group place at stake.
Wydad drew 0-0 away to Kano Pillars of Nigeria, who carried the burdens of playing with 10 men for 70 minutes after the early dismissal of midfielder Hillary Chukwu and trailing by two goals from their visit to the kingdom.
Casablanca will have two representatives among the last 16 in the premier African club competition that offers a 1.5-million-dollar first prize thanks to a late first-half goal from Senegalese import Mamadou Traore for Raja.
It secured the 'Green Devils' a 1-0 home win over 2009 African Confederation Cup winners Stade Malien of Mali and a third round place on the away-goal rule following a 2-1 reverse in Bamako.
Mazembe, Wydad and Raja are among nine African champions still in contention with Club Africain and Esperance of Tunisia, Al-Ahly of Egypt, Entente Setif of Algeria, Enyimba of Nigeria and ASEC Mimosas of Ivory Coast the others.
The Tunisian teams lost but first-leg leads saw them through although Club must await the inevitable 'green light' from the organisers after hooligans brought an early end to their clash with five-time champions Zamalek in Egypt.
A disallowed Zamalek goal in stoppage time with the Egyptians leading 2-1 but trailing by one goal on aggregate was the trigger for a pitch invasion at Cairo Stadium.
Security officials rescued the Algerian match officials but several visiting footballers were injured in incidents that led to the scrapping of plans to resume the Egyptian national championship in mid-April.
Esperance, who have lost star Nigeria-born striker Michael Eneramo from the team that finished runners-up to Mazembe last year, fell 2-0 to ASPAC in Benin after creating a five-goal cushion at home two weeks ago.
Ahly, rusty from lack of competitive match practice since the January revolt that ousted long-time strongman Hosni Mubarak, were grateful for a two-goal first leg lead as they fell 1-0 to SuperSport United in South Africa.
SuperSport rose above poor domestic form to hit a post before Jabulani Maluleke scored direct from a free kick and an Ahly strike force of 'Geddo' and Dominique da Silva never threatened goalkeeper Rowan Fernandez.
Burkina Faso was the place for goals as Setif shaded ASFA Yennenga 4-3 with Nabil Hemani scoring twice and Hadj Aissa and Abderrahmane Hachoud one each for the visitors who had established a two-goal advantage at home.
Enyimba of Nigeria struggled to a 2-1 home win over US Bitam of Gabon after a goalless first leg with Victor Barnabas and Josiah Madubuchi scoring for the 2003 and 2004 champions.
V Club of DR Congo, whose sole African title came 38 years ago, fell by the wayside after a 2-0 defeat to Cotonsport Garoua in Cameroon where Joel Babanda and Hilaire Moumi were the scorers.