"Arsenal are an outstanding, strong side," Klopp told a news conference on Friday. "Sanchez is probably back first time on the pitch so that gives this team another boost.
"That's one advantage for Arsenal, but I think we all can remember the atmosphere of (the Hoffenheim game) and that's what we want to have.
"It's Arsenal. Big experience, big quality, speed, technical skills, different systems, good players in each position on the pitch."
Arsenal have not won a league game at Anfield since 2012, but Klopp has a couple of injury concerns before the match.
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The German confirmed that Brazilian Philippe Coutinho (back) would play no part as he is still injured, while right-back Trent Alexander-Arnold is a doubt after suffering a dead leg against Hoffenheim.
Liverpool are drawn against Sevilla, Spartak Moscow and Maribor in the lucrative group stages of Europe's elite club competition and Klopp identified the Slovenian side as a potential threat.
Spanish side Sevilla beat Liverpool in the Europa League final in 2016, while Spartak are reigning Russian champions, but Klopp is as concerned by Maribor and said he needed to start doing his homework on them.
"The problem with our group is that the less you know about someone, the less respect you show them," said the German, whose team have avoided European heavyweights such as Barcelona, Real Madrid and Bayern Munich in the group stages.
"We remember the (Europa League) final against Sevilla and the quality they have shown in European competitions. Maribor, we don't know anything about."
(Reporting by Shrivathsa Sridhar in Bengaluru; Editing by David Holmes)
