Benitez said: "Steven has nerves of steel, he has great confidence in what he does on the pitch.
"We always know that in important games he is capable of scoring at the end. This time it was a penalty, as it was against Portsmouth.
"I always have confidence that he has the calmness to score under that sort of pressure.
"He does well in training with penalties against Pepe Reina and Diego Cavalieri so we all have confidence in him."
Gerrard has scored 14 of his 19 penalties for Liverpool and Benitez added: "We know that Steven will not give up, he'll keep going right to the end and it is no surprise when he scores such late goals now."
The debatable penalty, following a collision with Mariano Pernia, means Liverpool and Atletico both have eight points - with Marseille and PSV on three each - but both can qualify for the last 16 with home wins on November 26 against Marseille and PSV respectively.
Benitez insisted the penalty was correctly given, adding: "The referee missed a handball before the penalty, and it was given by the linesman who was very close.
"The point was crucial because we now only have to win one game to qualify. We had 22 shots, which is really good in a European match, but the figures do not mean anything really because you have to score.
"I felt we played much better at Tottenham at the weekend and lost, this time we faced a team who defended very deep and were well organised. We controlled everything, but not in the penalty area where it mattered.
"Agger had three great chances I would have expected him to score, especially as two of those chances were with his favoured left foot. But we are not taking our chances. I am saying this now after every game, but it is true. We must improve.
"Madrid are a very good team, they will progress in the tournament and I believe they can beat anyone once they get to the last 16. They are well organised and are very dangerous on the break where they have players with great quality. We were intent on qualifying now, Marseille winning against PSV made that possible, so we are disappointed that it could not be achieved."