The 20-year-old Belgian had little to do in the Atletico goal against his employers as he continues to impress on his loan stint in Spain.
Courtois told Canal Plus: "Four-one against the Champions League winners is great and we could have won 6-1 or 7-1. I had a little work to do. [Diego]Simeone's tactics were perfect. We played very well. We knew how to play and everything went very smoothly."