By Durosimi Thomas BBC Sport

Five former African champions are in danger of not making it to the group stage of this year's Champions League.

But they can still look forward to challenging for the Confederation Cup should they be eliminated from Africa's premier club tournament.

The eight Champions League losers this weekend will face the eight winners from the Confederation Cup to battle for places in the group stages of that event.

Current titleholders Enyimba of Nigeria have a lot to do as they travel to Angola to play Petro Atletico with the tie poised at 1-1 after the first leg in Aba.

Enyimba have struggled to maintain their championship winning form since lifting the African Super Cup in February against Etoile Sahel of Tunisia.

The Nigerian side are 13 points adrift of the leaders in their domestic league and there is still a protest from Ismaili, the Egyptian side they beat in last year's final, to be examined by Caf.

The side from Aba risk losing the trophy if they are found guilty of using an ineligible player in last year's final.

Petro were the first to score in Aba and should start as favourites on Sunday, but the side has been weakened by injuries and suspensions.

Striker Flavio, who scored the away goal, will be missing for the return match due to suspension while goalkeeper Marito is injured.

But Petro's Dutch coach Jan Brouwer says he is not too worried by the situation.

Ghanaian side Asante Kotoko, who had two players sent-off as they lost the first-leg 2-0, host Algerian champions USMA.

Algeria's USMA travel to take on Asante Kotoko in Ghana

The depleted Kotoko squad, managed by German coach Hans-Dieter Schmidt will be without defender Joe Hendricks and Kweku Essien.

USMA will still have to do without midfield ace Bilal Dziri and Amar Ammour.

They lost to JS Kabylie in the race for the Algerian title and their only hope of silverware this year rests with the Champions League.

Cameroon's former African champions Canon Yaounde are on the edge of elimination after they suffered a 2-0 defeat in Dakar to Senegal's Jeanne d'Arc.

However the outlook is better for a sixth former champion Esperance of Tunisia.

They lead their hosts Cotonsport Garoua of Cameroon 3-0.

Rwanda's giant killing APR travel to the Ivory Coast with a 1-0 lead over Africa Sports, while Sudanese side Al Hilal, who knocked out Egypt's Al Ahly, welcome SuperSport United of South Africa who have a 2-0 advantage from the first-leg.