The Blues threw away a two-goal lead at home to the Saints in the second half, but the Spaniard insists wayward finishing rather than poor defending was to blame
First-half goals from January signing Demba Ba and Eden Hazard had put the Blues firmly in control, but strikes from substitute Rickie Lambert and Jason Puncheon after the break ensured the spoils were shared.
The result keeps the west Londoners winless at home in 2013 and leaves their already unlikely title hopes in tatters, and Benitez believes a lack of ruthlessness in front of goal was to blame.
"We have to be more clinical," the Spaniard told reporters. "We had situations where we could score and we didn’t.
"I was telling the team at half-time ‘We have to score the third goal’, but we didn’t take the chances we had.
"In the second half we didn’t manage the game, we didn’t take our chances and we gave them hope that they could score, and they did."
Fernando Torres' arrival with 10 minutes to go was once again greeted with a mixture of indifference and hostility at Stamford Bridge, but Benitez insists the atmosphere is not affecting his £50 million man.
"Torres is professional, he is concentrated, and he tries to do his best," he added.
"At 2-0 up, it’s a question of experience and managing the game. We just had to stay compact, and then they would come and we would get more space.
"We were talking about the need to stop them making counterattacks but they did it, so obviously we made a mistake there.
"We have to defend as a unit a little bit better, especially when we’re winning. We have to improve."