United will take a healthy advantage into the return leg in Spain next week after running out 4-1 winners on the night.
Marcus Rashford, Antony, Bruno Fernandes and Wout Weghorst were all on target in a dominant display at Old Trafford.
Some Manchester United players were accused of downing tools at one stage during the record defeat at Anfield but Ten Hag feels they provided a positive response against their Spanish opponents.
"I think we played a very good game. At half time, we should have been up 3-0, but it was 1-1, we made one mistake and were punished for it, but I think we played well," he told BT Sport.
"We scored good goals, it was a good performance, it gave something to the fans, and they gave us something back as well, they were behind us and we're very grateful after Sunday.
"There was a good attitude from the start, we were on the front foot and we were good on the ball, finding the spare man in midfield and making good switches, making good runs behind and creating a lot of chances, so we are happy today.
"You always have to see how a team reacts after a setback and this is not the first time this season, I think it's five or six times, we can reset, we can bounce back, this team has character."
