The previous record was two, albeit in smaller tournaments.
After 17 days of competition, Morocco, South Africa, Senegal, Ivory Coast, Ghana, Cape Verde, Egypt, Congo and Algeria qualified for the round of 32.
Morocco was the first African nation to reach the semi-finals of the World Cup four years ago in Qatar and look capable of going deep again, having already held Brazil to a 1-1 draw. They are a co-host for the next edition of the World Cup in 2030.
Only six African countries had ever qualified for the knockout stage (several of them multiple times). The most in the same year had been two, in 2014 and '22.
This year's tournament has shown the strength of African soccer goes deep, with Cape Verde and Congo both surprise names in the round of 32.
Congo have a tall task in facing England next, but for now, the team are soaking in the moment.
"It's really historic for our country, Congo," forward Fiston Mayele said after the win over Uzbekistan.
"It's the first win and the first knockout stage. Today, I have to be proud here, and almost everywhere in my country, everyone is happy with what we did. We're proud to be Congolese, and I think we will keep going."
Mayele scored a goal 78 minutes in, sandwiched between two scores from Yoane Wissa — a penalty kick at the 68-minute mark and another in stoppage time.
Algeria advanced after the most thrilling ending to a game at this year's World Cup. They were 2-2 with Austria in stoppage time and seemed content to play for a draw until captain Riyad Mahrez struck suddenly for a go-ahead goal. Austria countered two minutes later on the final play of the game, but the draw was still enough to advance both teams.
After Congo's win, with the player of the game trophy by his side, Wissa described the long road it's been for his country to get to this point.
"It's only the second time we are in the World Cup, 52 years later. We started to qualify for the World Cup four years ago with this group," Wissa said.
"First game against Portugal, you drew. You lost against Colombia. Now you're losing one-nil after (10) minutes, so yeah, nothing is easy in football. We just need to show resilience, and when a time like this comes, you have to enjoy, because it's not easy."
Wissa hopes that the success in this World Cup shows that the future is bright for African soccer teams with young talent paving the way.
"Now every African team can dream big. The last World Cup, Morocco has been to the semi-final," Wissa said.
"What's coming next is good for the African teams, and we can see that now youngest players come earlier, and we showed our team with (Noah) Sadiki, (Ngal'ayel) Mukau, so that's good, and that shows our federation can dream big."
