The Giallorossi boss rejects suggestions his side will benefit from a rest over the weekend but hinted the Partenopei's loss to Atalanta could affect them.
The capital side saw its Serie A fixture with Parma abandoned because of adverse weather conditions after eight minutes Sunday, while Napoli suffered a potentially damaging 3-0 defeat.
Garcia does not believe his team's extra rest will help in its semifinal first leg but hinted Rafa Benitez's side could be affected following its weekend disappointment.
"A rest could benefit us and it could not," he told reporters. "Napoli played and lost though, and I think that'll have an effect. From a physical point of view we'll be fine, but we won't be in the rhythm that you have when you play - we haven't taken to the field for 10 days now."
But though Napoli is coming off a loss, Garcia still expects a stern test.
"We don't fear Napoli, we just respect them because they have a great side," he said. "It's a semifinal, played over two legs. It's a match that's 180 minutes long, maybe more. So tomorrow we just want to get closer to the final.
"This match is the most important simply because it is the next one we're playing. On Thursday though, we’ll focus again on the league. I'm sure Napoli are going to be at their best, because, like us, they want to make the final."