Marcello Trotta gave the League One side the lead in the first-half, before Oscar levelled in the second period.
The Bees once again took the lead after 73 minutes through Harry Forrester, but Fernando Torres notched a late equaliser to avoid a humiliating defeat.
Despite his side being favourites to advance, Benitez was happy with their performance and praised the fighting spirit shown to come back from behind:
“I was very pleased with the reaction of the players in the second half, we showed quality, character and it was much better.” He is quoted by Sky Sports.
“They were pushing and we knew it could be difficult, but we kept giving the ball away in simple situations which we could have managed better.
“In the second half we showed our real level, like we did last week against Arsenal. We have no excuses as to why we didn’t play well in the first half, we just didn’t do the right things.”
The Spaniard also praised Brentford’s performance, and thanked his scouts helping him to prepare for the clash:
“Brentford did well, we knew they would play with a high tempo and try to press. Our scouts did a good job because we knew everything they could do, but they did it well, so credit to them.”
Although they are not yet guaranteed a spot on the fifth round, Benitez is hopeful that his team can go all of the way and retain the trophy:
“For us, it’s important to do well in every competition. The top four is the priority, but we want to progress in the other competitions. The FA Cup is massive, Chelsea won it last season and we will try to do it again.”
The eventual winner of the tie will face Middlesbrough at the Riverside Stadium.