Chants of "You don't know what you're doing" were once again among the insults visiting fans hurled at the Spaniard, whose team selection and tactics have come under fire repeatedly in recent weeks.
But his substitutions could hardly be faulted after they were almost immediately followed by the goals that snatched a 2-2 draw and rescued a replay.
Benitez threw on Juan Mata at half-time having elected to rest the winger.
"I can guarantee that playing Mata, changing the game, we know what we are doing," said Benitez, who was forced to name forgotten man Yossi Benayoun in his team after losing several players to injury, suspension and international duty.
That may have explained the downbeat demeanour of the former Liverpool boss, who spent much of his pre-match press conference on Friday bemoaning the resources available.
It was pointed out yesterday that Chelsea did not even have that many players on the sidelines and their plight could be much worse.
"I agree with you," said Benitez, insisting he had done all he could to convince a reluctant board to spend more money.
Chelsea's need for reinforcements grew as their unprecedented fixture pile-up worsened, their FA Cup replay having to take place on fifth-round weekend, Saturday, February 16.
Benitez was hoping to be able to call on Petr Cech for Wednesday's Premier League game at Reading after the goalkeeper sat out yesterday's game with a knock.
David Luiz (ankle) remained a major doubt, while Eden Hazard will serve the second instalment of what will be an extended ban if the Football Association get their way.