After taking an early lead in that clash with the Serie A giants courtesy of a Fikayo Tomori own goal, Jurgen Klopp’s side missed a penalty through Mohamed Salah before Ante Rebic and Brahim Diaz struck for the Rossoneri with a quick-fire double before the interval.
However, Liverpool would not be denied as Salah and Jordan Henderson both netted in the second half to kick-off their quest for a seventh European Cup with an eventful victory.
They also lie at the summit of the Premier League after six matches in 2021/22, a point clear of Manchester City, Chelsea, Manchester United and Everton after being held to a thrilling 3-3 tie at Brentford on Saturday evening.
Keita suffered a foot injury during last week’s Carabao Cup defeat of Norwich and missed the subsequent meeting with Brentford, though was training at Melwood on Monday before the flight to Portugal.
Right-back Neco Williams has also now returned to training for the first time this season, though Thiago Alcantara (calf) and Harvey Elliott (ankle) are still sidelined.
Klopp must weigh up whether to make changes for the meeting with Porto, with defending champions Manchester City paying a visit to Merseyside in the Premier League on Sunday.
Liverpool predicted XI: Alisson, Alexander-Arnold, Van Dijk, Gomez, Robertson, Henderson, Fabinho, Keita, Salah, Firmino, Mane
Tuesday 28 September 8pm BST
Venue Estadio do Dragao, Porto
Liverpool squad from: Alisson, Alexander-Arnold, Gomez, Konate, Tsimikas, Fabinho, Henderson, Keita, Salah, Firmino, Mane, Kelleher, Adrian, N Williams, Van Dijk, Matip, Phillips, Robertson, Milner, Jones, Oxlade-Chamberlain, Minamino, Origi
Injured: Thiago Alcantara (calf), Harvey Elliott (ankle)