Henrichs: Haaland ate us up - it's a brutally bitter evening for us
Haaland scored five goals, including a first half hat-trick, as City blew the German visitors out of the water to qualify 8-1 on aggregate.
Henrichs was at a loss to explain how his side, who came into the match on level pegging from the first leg, could lose so convincingly.
"I think we were eaten up out there," he said. "I've never lost 7-0 in my career. It's a totally brutally bitter evening for us."
Henrichs said Haaland, who moved from Bundesliga side Borussia Dortmund to Manchester City last season, dominated Leipzig with his physicality.
"He's a brutally physical player. He's difficult to defend and brings so much to the game.
"The way he played today says a lot about his quality."
Asked about a contentious first-half penalty the German defender conceded after a VAR review, Henrichs said "we can't talk about VAR, we need to talk about our own performance."
Leipzig manager Marco Rose, who coached Haaland at Dortmund and Red Bull Salzburg, said he knew the threat posed by the Norwegian.
"I know Erling well and I know his quality - and how he can perform. When Erling sees the goal, he wants to score."
Haaland, 22, has scored 39 goals in 36 games for City, including 10 goals in six matches in the Champions League.
