Villa suffered a 2-1 defeat at Chelsea on Wednesday night in a game surrounded by controversy, with boss Paul Lambert furious at two refereeing decisions.
But Weimann insists his side will take their new-found confidence into their first home game of the season.
"We will go away with our heads held high and go again on Saturday against Liverpool," said Weimann.
"Everyone is down now because we should have got something from the Chelsea game.
"But we go away with loads of positives from both games.
"We won at the Emirates and going to Stamford Bridge and playing the way we did was brilliant. We will take that into the next few games.
"We have loads of confidence. Everyone is looking forward to playing at Villa Park for the first time this season."