Jeancy Mboma scored early in the second half to earn Tanzanian club Singida Black Stars a 1-0 win over Kenyan hosts Tusker in a CAF Confederation Cup qualifier on Sunday.
With a home return match to come on October 25, Singida are set to secure a place in the 16-club group draw.
Winning marked a return to form by the Black Stars, who trail leaders Simba by 13 points after eight rounds of the Tanzania Premier League having won only three matches.
Singida were the most impressive aggregate winners in the previous qualifying round, putting 10 goals past Al Ghazala Wau from South Sudan.
Meanwhile, Tashreeq Morris converted an added-time penalty to complete a 3-1 home victory for African debutants Durban City over Mauritian side Port Louis.
Hashim Domingo and Uruguayan Gaston Sirino had given City a two-goal advantage before Louis Roussety halved the deficit.
After 13 failed attempts by eight clubs, Port Louis are hoping to become the first club from Mauritius to qualify for the group phase.
Durban gained promotion to the top flight in South Africa only last season. They qualified for the second-tier African competition by winning the FA Cup.
Title-holders USM Alger of Algeria secured a place in the group phase without kicking a ball after opponents Panthers from Equatorial Guinea withdrew, citing financial problems.
Panthers could not host the first leg because Equatorial Guinea, who staged the 2015 Africa Cup of Nations at four venues, no longer has a stadium that meets international standards.