The Bundesliga side put one foot in the group stages of Europe's premier club competition with a 3-2 win at FC Copenhagen on Tuesday.
Goals from Stefan Kiessling, Karim Bellarabi and Son Heung-min helped Leverkusen to victory in Denmark and they are now firm favourites to progress.
But Schmidt – who moved from Red Bull Salzburg to replace Sami Hyypia at the BayArena – knows improvements can be made in the final third and is not expecting his men to ease off in the return clash in Germany.
"Winning away is a good starting point, but it could have been even better if we had won by a larger margin," Schmidt said.
"There were many good moments from us, especially in the second half, but we could have been more efficient.
"Had we been more clinical it would have been a clearer result. We deserved a bigger win.
"There is no time to relax. We have to prepare for the return leg and use the weapons that we have. If we manage to do so I'm very optimistic.
"You have to play well against a team like FC Copenhagen. The desire from the players to proceed to the group stage is so great that they won't take the second leg lightly."
Leverkusen – Champions League finalists in 2002 – reached the round of 16 in last season's competition.
