Milner singled Mane out for praise, highlighting his all-round contribution to the team as well as his goalscoring exploits, and insisted that Porto are a "very good side".
However, the 32-year-old was pleased with Liverpool's work in Portugal and believes that, given his side's talented attacking players, more goals could have been on the horizon against the 2003-04 champions.
"Mane does his job and does a great job for the team," Milner told BT Sport. "People see his flair and the goals that he scores but he does a great job working for the team.
"Porto are a very good side. It's a tough place to come, you could see the crowd and the way they were even at the end.
"We wanted to keep a clean sheet and with the players we have we always have the chance to score an away goal. I thought we could have scored more."
Liverpool will be favourites to progress to the quarter-finals of the competition, with the return leg at Anfield taking place on Tuesday, March 6.