Hurt during the first leg of Liverpool's Champions League semi-final showdown with Barcelona, Keita spent nearly two months out before making his comeback in the final 30 minutes of Saturday's 2-2 draw with a plucky Madagascar.
His impact was immediate in Alexandria as Guinea equalised within four minutes of his introduction.
"His arrival hurt us, obviously. Guinea are a very good team," said Madagascar coach Nicolas Dupuis.
Now, with their playmaker back in the side Guinea have the chance to send a message against Nigeria on Wednesday.
"He gives a lot, he's a leader in his own way. We need him. He helps us benefit from his experience in big matches. It's a bonus to have him," forward Sory Kaba, scorer of the first goal against Madagascar, told AFP.
At Liverpool just as here in Egypt, Keita, 24, is again operating in the shadows of club team-mates Mohamed Salah and Sadio Mane.
"There is really no doubt about the boy, he is an outstanding player," said Klopp, who stumped up €60 million ($68 million) to lure him from Leipzig and then thrust him into a starting role at Anfield.
"I am looking forward to our common future," said Klopp. "You see it every day, wow, there is so much to come and there is so much influence he can have on each game."
With 33 appearances and three goals in his debut Premier League campaign, the Conakry native has not been daunted as the heir to Liverpool's number eight shirt previously worn by club legend Steven Gerrard.
While the thigh injury forced him to miss the Champions League final win over Tottenham, Keita won his battle against the clock to represent his country at the Cup of Nations, his recovery cloaked in suspense but a huge relief for a nation of 12 million inhabitants.
In 2015, his first taste of the competition, Keita appeared as a substitute during a 3-0 defeat by Ghana in the quarter-finals, a stage Guinea haven't gone beyond since finishing as runners-up in 1976. Having failed to qualify two years ago, they are hoping their midfield engine can drive a new generation to greater heights.
"We're going to firstly try and get out of our somewhat difficult group," Keita said modestly. "We'll see what happens next."
It was Keita who scored the winner in a 3-2 victory away to Ivory Coast at the outset of qualifying, a result that hinted at Guinea's potential.
Having initially declared Keita would miss the competition, Klopp will certainly be paying close attention to his progress in Egypt, where he could come up against a host nation heavily relying on Salah in the last eight.