A riot that broke out in the 81st minute of Kenya's Africa Cup of Nations qualifying clash with Guinea-Bissau saw police fire tear gas on supporters as well as drive a police car onto the field of play.
Kenya now faces potential sanctions from FIFA after the unrest, which came after a controversial goal that Zimbabwean referee Norman Matemela ruled had crossed the line despite protests from the Kenya players.
Eventually after a 30 minute interruption Guinea-Bissau were able to jump Congo and Zambia to go top of Group E with a 1-0 win.
Paulo Torres' men were third heading into the fourth round of fixtures after beating Kenya by the same scoreline on home soil.
But just a second win of the campaign proved enough to put Guinea-Bissau in the driving seat, with Congo and Zambia drawing 1-1 later in the day to leave both a point adrift of the summit.
Having come close to opening the scoring through Victor Wanyama, Kenya eventually fell behind to a Niche strike in the 81st minute.
In Group H, Ghana's 100 per cent record came to an end as they were held to a goalless draw by Mozambique, who hit the crossbar through Domingues.
Comoros failed to follow up their first competitive victory – a 1-0 win against Botswana on Thursday – with a second triumph over the same opponents, losing 2-1 after initially taking the lead.
In the day's remaining fixture, Benin triumphed 4-1 over South Sudan to move top of Group C.
Meanwhile, Chad announced their withdrawal from qualifying on Sunday in a huge blow to Nigeria's chances of making it out of Group G.
Only one team will now progress from the pool, with Egypt two points clear heading into the final two fixtures.