Mo Salah and Roberto Firmino both notched braces in Tuesday’s 5-1 thrashing of the Portuguese giants at the Estadio do Dragao, which has been a happy hunting ground for Jurgen Klopp’s men in recent times.
That latest thumping victory means prolific Liverpool - who host Manchester City in a high-profile Premier League showdown on Sunday - have kicked off their quest for a seventh European crown with back-to-back wins after coming from behind to topple AC Milan in a five-goal thriller at Anfield a fortnight ago.
They sit pretty at the top of Group B and two points ahead of Atletico Madrid, who beat 10-man AC Milan in Italy on Tuesday night courtesy of a last-gasp 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 last 16 is far from secured.
"It is definitely not job done, because there is four games still to play and it is a very tough group," the England midfielder told BT Sport.
"But we have had two very good performances against Milan and now Porto, we have applied ourselves very well and got the results we deserved. It is a good start, but far from over.
"We will be disappointed to concede as I thought we were dominant throughout the game.
"We scored some brilliant goals and played good football, so we have got to be pleased as it is a difficult place to come."
On his latest milestone for Liverpool, Henderson added: "I can't describe the feeling. I still get it every time I put the shirt on. It's an honour and hopefully I can do it many more times in the future."