Jordan Henderson, playing in a more advanced midfield position than normal, cut the visitors' defence open for the England global to square for Firmino to tap into an empty net.
Spurs went on to win the game 1-0 courtesy of a second-half goal from Son Heung-min.
"I think they [now] have experience, but also a lot of talent in the team, so they can be very risky on that front as well". He obviously likes the position.
The Liverpool boss said: "We deserved the win 100 per cent, we scored two wonderful goals, we were in a lot of really unsafe situations".More news: Black hole event horizon: Here is what it looks like
There remains plenty of work to do for the Premier League leaders, who will be disappointed they were unable to gain a bigger advantage for next week's second leg. Klopp has picked his first-choice lineup in hopes of striding to a commanding lead after the first leg, but a plucky Porto side will be searching for a single chance to put Liverpool on their heels.
"We gave a few too many set pieces away - I think Porto score about 40% of their goals from set pieces".
" There were one or two counter-attacks, and in the second half we lost a little bit of our rhythm and a little bit of our direction, and we should've played a little bit more in behind."
"Two-nil is a really good result. He got better minute by minute last game and he continued that", added the Liverpool boss.More news: Ole Gunnar Solskjaer could lose seven Man United players this summer
"We knew we would have to play the second game, that's how it is". But we need to do it a little bit better, especially than in the second half. I would have bought it before the game and I will take it now!
Klopp joked after the Porto game that he should say sorry to Henderson for playing him in the wrong position for the last 18 months.
The defensive solidity they have brought to the Merseyside team has also benefited full-backs Trent Alexander-Arnold and Andrew Robertson, who have provided their teammates with a handful of assists this season.
The result extended Liverpool's unbeaten run at home in European competitions to 21 games (15 wins and six draws).More news: Hopes of Brexit delay pinned on key talks