The legendary Galatasaray goalkeeper feels the former Villarreal man should keep his Real Madrid place ahead of Iker Casillas
The Spain skipper fractured his hand in January, prompting the signing of the former Sevilla man, and the 46-year-old feels he has performed admirably.
"I believe that the decision taken by [Jose] Mourinho is correct because Diego Lopez has done a great job since he came to Madrid. He has great capabilities and, in my opinion, is in great physical condition," Taffarel told AS.
"I saw him in the tie against Manchester United and was brilliant. Really, Lopez's performances for Madrid have been perfect.
"Mourinho's decision is correct. A coach must think only of the team's success, analyse who is playing well and put them in the starting line-up.
"You cannot turn this into a controversial topic. Diego is perfect and if he keeps playing well, he will continue as a starter. Mourinho is absolutely right on this issue."
Taffarel, who played for Galatasaray as a player and now coaches them, admits that his side face an uphill task against the Spanish champions following their 3-0 first-leg loss, but vowed that they would fight.
"Everything is possible in football. It is difficult to say that we will win 4-0, but we are the Galatasaray.
"In addition, playing at the Turk Telekom Arena will be an advantage for us. Our fans are very passionate. There will be a spectacular atmosphere.
"We have a small chance to qualify and I am convinced that we will play better than at the Bernabeu. We have 90 minutes ahead of us to show our quality."