Mo Salah and Roberto Firmino both scored braces in the Portuguese giants’ 5-1 loss on Tuesday at the Estadio do Dragao, which has been a happy hunting ground for Jurgen Klopp’s men in recent times.
This latest resounding victory means the prolific Liverpool – who host Manchester City in a top Premier League clash on Sunday – launched their quest for a seventh European crown with consecutive wins after coming back from behind to topple AC Milan in a five-goal thriller at Anfield a fortnight ago.
They are well placed at the top of Group B and two points ahead of Atletico Madrid, who beat AC Milan to 10 in Italy on Tuesday night thanks to a last-breath penalty from Reds legend Luis Suarez.
However, Henderson, who made his 400th appearance for Liverpool in Portugal, was keen to stress that qualification for the round of 16 is far from assured.
“It is certainly not a job done, as there are four games left to play and it is a very difficult group,” the England midfielder told BT Sport.
“But we had two very good performances against Milan and now Porto, we applied very well and got the results we deserved. It’s a good start, but far from over.
“We will be disappointed to concede as I thought we were dominant throughout the game.
“We scored brilliant goals and played good football so we have to be happy because it’s a tough place to come.”
Commenting on his latest milestone for Liverpool, Henderson added: “I can’t describe the feeling. I always feel it every time I put the shirt on. It’s an honor and I hope I can do it several times at the future.”