Veteran defender Carlos 'Kaly' Alonso was the toast of Angolan football after he scored in the second additional minute to cancel a lead Tunisia had held since the sixth minute thanks to young midfielder Youssef Msakni.
Senegal were lucky to be level in the first game of a Group D double-header before breaking Rwandan hearts when Moustapha Kasse scored one minute from full-time and Mohamed Diop added a second goal 120 seconds later.
Victory earned Senegal three points in the Port Sudan-based mini-league and top place after the first series of matches while Angola and Tunisia collected one each and pointless Rwanda prop up the table.
A thrilling climax to each match followed several weekend shocks as a South African side composed largely of third-tier league footballers mocked the Group B form book with a come-from-behind 2-1 triumph over favoured Ghana.
Cameroon delivered an even bigger upset by winning 2-0 against title holders and tournament favourites Democratic Republic of Congo, who fielded seven of the TP Mazembe side that reached the Club World Cup final last December.
Sudan, Algeria, shock qualifiers Niger and Ivory Coast were other winners in the first round of group games in a tournament restricted to home-based footballers.
An early goal was just the boost Tunisia needed after having their build-up disrupted by political upheaval in the North African state that led to long-time ruler Zine El Abidine Ben Ali fleeing the country.
Angola, who spent several weeks training in Brazil under new coach Lito Vidigal, must have feared the worst as stadium clocks ticked past the 90-minute mark only for 'Kaly' to emerge as the unlikely saviour.
Territorially dominant Rwanda squandered several chances and a thunderous Peter Kagabo drive came back off the woodwork as they pinned Senegal inside their half for much of the match.
But with a goalless draw seemingly inevitable, substitute Kasse pounced on a rebound and fired the ball past goalkeeper Jean-Claude Ndoli to sting the Rwandan 'Wasps'.
Diop drilled a free kick into the net two minutes later to leave Ghana-born Rwanda coach Sellas Tetteh speechless and his side needing a win over Tunisia Friday to have a realistic chance of making the quarter-finals.