Johannesburg - SuperSport United were runners-up in the previous CAF Confederation Cup, but could struggle to get past Petro Atletico of Angola in a last-32 tie this season.
The clubs clash in Luanda on Tuesday with the return match in Pretoria on March 16 and the overall winners advance to a play-off against a CAF Champions League last-32 loser.
Coach Eric Tinkler has quit SuperSport after failing to halt a slump since they lost 2-1 on aggregate to TP Mazembe of the Democratic Republic of Congo in the Confederation Cup final.
United, who were expected to challenge for the South African Premiership title this season, find themselves mired in a relegation battle with seven rounds remaining.
They also made first round exits from the South African League Cup and FA Cup competitions, leaving Tinkler with no option but to fall on his sword.
His place has been taken by long-serving assistant Kaitano Tembo, a former Zimbabwe defender, with a review planned at the end of the domestic season in May.
Tembo is no stranger to the Confederation Cup - the African equivalent of the Europa League - having guided SuperSport through the group stage last year before Tinkler took charge.
"I am here to perform to the best of my ability," said Tembo after his sudden elevation. "I am like a cadre if you put it in political terms.
"SuperSport come first. It is not about me, it is all about the team. All of us need to take responsibility and perform better than of late."
A blow for SuperSport was the recent sale of 2017 Confederation Cup leading scorer and New Zealand international Jeremy Brockie to fellow Pretoria club Mamelodi Sundowns.
While United had a preliminary round bye in Africa, Petro served notice of their intentions by hammering Masters Security of Malawi 5-0 in Luanda before a goalless second leg.
National team captain Ricardo Job Estevao pulls the strings in midfield for crowd-pullers Petro, who are coached by Brazilian Beto Bianchi.
There are five former African champions in last-32 first leg action this Tuesday and Wednesday, including nine-time CAF title winners Zamalek of Egypt.
The Cairo-based "White Knights" are away to inexperienced Welayta Dicha of Ethiopia, who struggled to overcome Zimamoto of Zanzibar and could face a torrid time.
Raja Casablanca, whose stars played key roles in Morocco winning the African Nations Championship last month, host Nouadhibou of Mauritania and should triumph with several goals to spare.