Southern Africa countries Mozambique and Zambia established 1-0 first-leg leads Wednesday through contrasting goals in 2018 World Cup second round qualifiers.
An unstoppable 55th-minute drive by Helder Pelembe from just outside the box earned the Mozambican Mambas (Snakes) a 1-0 victory over Gabon at Estadio Zimpeto in Maputo.
At the other end of the continent, a defensive mix-up by Sudan at Karima Stadium north of Khartoum gifted Winston Kalengo a 28th-minute winner for 2012 African champions Zambia.
Mozambique began and ended the opening half impressively while Gabon created several chances in between with Guelor Kanga rattling the woodwork.
The lone goal came when South Africa-based Pelembe ran on to a through pass and cracked the ball past veteran goalkeeper and captain Didier Ovono.
A muscular injury ruled out star Gabon striker Pierre-Emerick Aubameyang, scorer of 22 goals in 20 appearances this season for Bundesliga outfit Borussia Dortmund.
Gabonese officials did not immediately clarify whether the 26-year-old would be available for the return match in Libreville Saturday.
Sudan goalkeeper Akram El Hadi Salim and defender Ramadan Agab must share the blame for the Zambian goal on a part-dustbowl pitch unsuitable for international football.
Each hesitated, waiting for the other to clear a ball played into the penalty area, and Kalengo nipped in to fire home at Karima Stadium.
Victory installs Zambia as favourites to qualify after the second leg in Ndola Sunday and reach the five-group third round with the winners qualifying for the World Cup in Russia.