The 30-year-old, who played for Watford before moving to China two years ago, has scored three goals at the African football showpiece in Egypt.
That tally gives him a share of the lead in the Golden Boot race with Senegalese Sadio Mane, Congolese Cedric Bakambu and Algerian Adam Ounas.
Two of his goals came in the 3-2 second round defeat of defending champions Cameroon, and he could have finished with four having hit the woodwork and been foiled by a superb save.
A few hours after Nigeria triumphed last Saturday, South Africa stunned hosts and pre-tournament favourites Egypt 1-0 in Cairo with Thembinkosi Lorch snatching a late winner.
Most South Africans had written off Bafana Bafana (The Boys) after a dismal one-win group campaign and were discussing who should replace unpopular coach Stuart Baxter.
If Nigeria and South Africa can replicate their last-16 form, a titanic struggle for supremacy is on the cards at the Cairo International Stadium.
Here, AFP Sport looks at the first quarter-final, between Senegal and giantkillers Benin at another Cairo stadium, and the showdown between Nigeria and South Africa.
Nigeria v South Africa
Ighalo says the 2-0 group stage loss to outsiders Madagascar was a massive wake-up call that worked in favour of the Super Eagles.
“Any thoughts we had of an easy passage to the closing stages vanished after that defeat. We realised that many teams were motivated by playing Nigeria and raised their game against us.
“While I have enjoyed scoring three times in Egypt, it is irrelevant who puts the ball in the net as long as he is a Nigerian.
“We want to win the title a fourth time, but South Africa also want to get their hands on the trophy, as do all the other title contenders.”
South Africa have consistently battled against Nigeria, with a shock 2019 Cup of Nations qualifying triumph in Uyo their lone competitive victory over them.
Benin v Senegal
Liverpool star Mane does not want to take any more penalties at the Cup of Nations after missing two of three he was entrusted with during the tournament.
The 27-year-old missed and scored from spot-kicks in a convincing group win over Kenya and fluffed another penalty when they edged Uganda in a last-16 encounter.
“I missed penalties in two games and that it is not a good ratio,” admitted the forward who shared the last Premier League Golden Boot award with team-mate Mohamed Salah and Pierre-Emerick Aubameyang of Arsenal.
Benin shocked Morocco, considered one of the strongest title contenders, by winning on penalties after playing most of extra-time a man short when Khaled Adenon was red-carded.
“This was the greatest achievement in Benin football history,” said veteran forward Mickael Pote. “We may not be the best team in Egypt, but our team spirit is second to none.”
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