Atletico finished as group winners after dispatching Rennes in midweek, but return to Primer Division action against Real Betis knowing they must improve on the domestic front.
Two successive La Liga defeats have seen them slide down the table, but under-pressure Manzano refuses to be despondent.
"We were expecting a negative atmosphere against Rennes because of recent results, but we responded with a win," he said.
"I'm very satisfied with having qualified because it wasn't easy. I'd like to thank the players for all their hard work."
Thibaut Courtois and Mario Suarez are likely to return for Atletico after being rested in midweek and there could also be a start for Jose Antonio Reyes, who has been linked with a move to Sevilla.
Real Betis striker Jorge Molina insists his side, who sit just one point above relegation, scent blood at the Vicente Calderon.
"Atletico are not having the best of times at the moment but we must try and focus more on ourselves," he said.
"We will go there and try to get all three points," he added.
Real Betis were humbled by Cordoba after fielding a fringe side in the midweek Copa del Rey match so coach Pepe Mel is likely to revert en masse to his first choice line-up for a league game which has been given added significance by that defeat.