Vipers SC crashed out of the CAF Champions League at the preliminary first round after a goalless draw with Nouadhibou in Nouakchott.
The Venoms, who drew 1-1 in the reverse fixture seven days earlier, needed a win in Mauritania but could not find a breakthrough despite late chances from substitutes Yunus Sentamu and Ceaser Manzoki.
Starters Nicholas Mwere and Hilary Mukundane also went close in an evenly contested affair, but the Mauritanians held firm to progress on aggregate.
Vipers would have faced San Pedro of Ivory Coast in the next round had they advanced, but the Kitende outfit now turn attention to defending the StarTimes Uganda Premier League title for a third straight season.
That defence has already stumbled, with Vipers opening their domestic campaign with a 1-0 defeat to Entebbe UPPC.
They return to action on Saturday when they host newly promoted Ntugasaze at St Mary's Stadium, Kitende.
The argument doing the rounds is whether Vipers' continental struggles point to a squad too thin for both fronts, or simply the reality of east African clubs against better-funded north and west African opposition.
Key facts
- Competition: CAF Champions League, preliminary first round
- Aggregate: Nouadhibou 1-1 Vipers (Nouadhibou advance)
- Venue: Nouakchott, Mauritania
- Vipers chances: Yunus Sentamu, Ceaser Manzoki, Nicholas Mwere, Hilary Mukundane
- Next fixture: Vipers vs Ntugasaze, Saturday, St Mary's Stadium, Kitende
- League form: Lost 1-0 to Entebbe UPPC in opener
Watch the Highlights
Source: Uganda Premier League