Manchester United winger Amad Diallo scored the only goal as Ivory Coast got their Africa Cup of Nations defence off to a winning start.
The West African nation are vying to become the first country to win consecutive AFCONs since Egypt in 2010.
They faced Mozambique, ranked some 60 places below them in FIFA's rankings, in their opening group fixture on Wednesday night in what turned out to be a surprisingly close game.
Despite boasting stars such as Franck Kessie, Wilfried Zaha and Amad, it took Ivory Coast until after the interval to break the deadlock.
After latching on to a Kessie knockdown in the box, Amad slotted home with a sweetly-struck effort on his right foot before wheeling away to celebrate in the thrashing Moroccan rain.
It proved to be the match's only goal and one which sent Ivory Coast joint top of Group F with their next opponents, Cameroon.
The Cameroonians secured a 1-0 win in their first game of the group stage against Gabon thanks to a goal from Karl Etta Eyong, assisted by none other than Bryan Mbeumo.
Cameroon and Ivory Coast, two of the favourites for the tournament, go head-to-head on Sunday night in Marrakech, Morocco, in a clash which may well decide the group.
Amad and Mbeumo have both enjoyed impressive starts to this campaign after the latter moved north from Brentford in a deal worth £65million last summer.
Mbeumo has notched seven goals and provided one assist while Amad, playing in a more defensive wing-back position, has scored two and provided three.
Ruben Amorim's side face Newcastle United in this year's sole Premier League Boxing Day fixture without Mbeumo, Amad and Noussair Mazraoui, who is also at AFCON with Morocco.
The full-back got his tournament off to a winning start on Sunday as Morocco beat Comoros 2-0 in Rabat.