South Africa will return to the FIFA World Cup for the first time since hosting the tournament in 2010 after narrowly claiming top spot in their qualifying group ahead of Nigeria and Benin.
Benin, chasing a maiden World Cup appearance, started the last round of matches at the summit of Group C, two points ahead of South Africa and three in front of Nigeria.
But the team led by former Super Eagles coach Gernot Rohr fell to a 4-0 defeat away in Uyo, with Victor Osimhen grabbing a hat-trick for the hosts, a result that saw the Cheetahs slip to third, below their opponents on goal difference.
That opened the door to the South Africans, and Bafana Bafana capitalised as they eased to a 3-0 home win over Rwanda.
Thalente Mbatha fired home in the fifth minute, Oswin Appollis whipped in a second midway through the first half and Evidence Makgopa headed in the third in the 72nd minute in Mbombela.
South Africa become the seventh African team to reach the expanded 48-team finals, joining Morocco, Tunisia, Egypt, Algeria, Ghana and Cape Verde.
There will be relief that the 3-0 forfeit imposed by FIFA for fielding an ineligible player in their victory over Lesotho in March has not cost them.
That decision, announced earlier this month, saw Bafana drop from the top of the group to second, behind Benin on goal difference, heading into the final two rounds of preliminaries.
Hugo Broos' men let two more points slip when they failed to beat bottom side Zimbabwe in a nominal away game in front of a packed Durban crowd on Friday - but Benin's defeat in the West African derby gave his side a chance to redeem themselves against the Wasps.
Africa's final two automatic qualifying spots, either Senegal or DR Congo from Group B and Ivory Coast or Gabon from Group F, will be decided later on Tuesday.
Nigeria, meanwhile, could still reach next year's tournament via an arduous route potentially involving an extra four matches.
Victory was enough for the Super Eagles to secure one of four spaces in next month's African play-offs, with the overall winner of that progressing to Fifa's final six-team inter-continental qualifier which is scheduled to be held next March.
Those games will decide the last two qualifiers for the expanded 48-team World Cup in Canada, Mexico and the United States.
Osimhen to rescue for Super Eagles
There has been plenty of soul-searching over the past few months in Abuja, beyond the capital and among Nigeria's vast diaspora at the prospect of missing a second successive edition of the World Cup.
But, thanks to Osimhen, the Super Eagles still have hope.
There is no denying that regular changes in the dugout have affected Nigeria, but an undeniably talented squad failed to win any of the five game they played when the Galatasaray striker was absent through injury.
Under Jose Peseiro the team drew their first two matches against minnows Lesotho and Zimbabwe, while Peseiro's successor Finidi George claimed a home point against South Africa but departed straight after a 2-1 defeat away against Benin in June last year which left Nigeria in a desperate-looking position.
Eric Chelle was tasked with somehow finding a route to the World Cup when he was appointed in January and the former Mali boss made a good start with victory over Rwanda, but Zimbabwe then grabbed a 90th-minute equaliser in Uyo to puncture momentum.
After beating Rwanda at home, Nigeria then showed a surprisingly lack of urgency or intent without Osimhen while drawing 1-1 in South Africa last month - a result which left the Super Eagles needing other results to go their way to top the group and claim automatic qualification.
A nervy win over Lesotho on Friday set up the crunch encounter against Benin where Osimhen's clinical finishing proved to be the difference.
First the 26-year-old converted Samuel Chukwueze's through ball in the third minute, then he headed in a deep right-wing cross from the Fulham winger to double the lead eight minutes before the break.
Osimhen completed his treble with a stunning diving header which went in off a post from Moses Simon's free-kick in the 51st minute.
Nigeria made sure of their play-off spot in the first minute of stoppage time when Frank Onyeka volleyed in another Simon cross to make it 4-0 and add a gloss to the scoreline which belied the Super Eagles' rollercoaster qualifying campaign.
Keeping the influential Osimhen fit for next month's continental play-offs will be crucial if Nigeria are to take their place at the World Cup finals next year.
BBC