Trent Alexander-Arnold's free-kick and a second-half own goal handed the Reds a commanding advantage in Germany.
Trent Alexander-Arnold's free-kick and a second-half own goal handed the Reds a commanding advantage in Germany, but Mark Uth's late strike provided Hoffenheim with a glimmer of hope ahead of the return at Anfield.
Klopp rotated his squad for Saturday's 1-0 victory over Crystal Palace in the Premier League, making five changes to the team with Wednesday's European encounter weighing heavily on his mind.
It is three years since the Anfield outfit, five times European champions, last graced the group stage of the continent's elite club competition.
"The performance and the result were not perfect, far from it. We still have much to do in this tie," Klopp said in Liverpool's matchday programme at the weekend.
The club have also rejected a third bid from Barcelona for star playmaker Philippe Coutinho, turning down a reported offer worth around £114 million ($146.5 million, 124.7 million euros).
The 25-year-old Brazilian has submitted a transfer request, but Liverpool have publicly stated Coutinho, currently sidelined by a back problem, is not for sale at any price.
Hoffenheim started the new Bundesliga campaign with a 1-0 victory at home to Werder Bremen, and Germany midfielder Kerem Demirbay still harbours hope of stunning Liverpool in the second leg.
"We could achieve something extraordinary there. We could turn it around. We will give everything to do that," said Demirbay, who was part of Germany's Confederations Cup-winning side in Russia.
Scottish champions Celtic are all but assured of a return to the group phase following a 5-0 demolition of Astana in last week's first leg in Glasgow.
Brendan Rodgers' side stretched their unbeaten domestic run to 52 matches with Saturday's 2-0 victory at Kilmarnock and have conceded just once in nine matches this season.
James Forrest struck the Hoops' opener at Rugby Park but insists Celtic cannot afford to be overconfident ahead of their 6,000km trip to Kazakhstan.
"We just can't get complacent, we need to make sure we start the game well and start positive and hopefully get a positive result," said Forrest.
Nice face a monumental task to overturn a 2-0 deficit against Napoli on Tuesday, but the French side will be boosted by the presence of Mario Balotelli and new recruit Wesley Sneijder.
The Dutchman, a Champions League winner with Inter Milan in 2010, played 85 minutes in his debut on Saturday as Nice downed Guingamp 2-0 for their first points of the season.
"I feel good, especially with a win, you feel really good. As for my performance, I know I can do better," Sneijder, who joined on a free transfer following his exit from Galatasaray, told Canal+.
"It was my first match so I need to get to know the guys. The second half was better than the first but I still need time."
Balotelli also made his first appearance of the league season after coming on a second-half substitute following his return from injury.
Sevilla will fancy their chances of qualifying for a third straight group stage campaign as they hold a 2-1 edge over Turkey's Istanbul Basaksehir, who have never won away from home in Europe.