Smith views the showdown with Grand Slam-chasing Ireland at the Aviva Stadium as a "free swing" on the basis no one is giving England even a puncher's chance of ruining the St Patrick's Day celebrations.
Having crashed to a record-breaking 53-10 defeat by France at Twickenham in round four, they have been installed as 7-1 underdogs to upstage the world's number one ranked side in their last competitive fixture before the World Cup.
Failure would see them finish with just two wins for a third successive Six Nations, but Smith insists his team will come out fighting.
"We're in a tough period at the minute and it's perfect for us," the Harlequins fly-half said.
"We've got to get better quickly because the challenge doesn't come much greater than Ireland away in Dublin.
"There's only one way to go now and that's to stand up and fight as hard as we can and play as hard as we can for the shirt.
"We've spoken about sticking together because there's going to be a lot of noise and a lot of pressure on us. We've got to become tighter as opposed to splinter.
"This is a big test of our togetherness as a squad and of our resolve. There's no better week for this than a free swing at Ireland.
"Time is against us, but I believe we've still got time. With the characters we've got in the group we can turn things around very quickly.
"We've got a week now to right some wrongs and we've got to get on the same page quickly."
France amassed seven tries as they rampaged through Twickenham, inflicting England's heaviest defeat in the tournament since it was founded in 1882.
"We didn't build up in the week to lose like that," said Smith, whose return at fly-half quickly turned into a nightmare as England were pulverised in the contact area.
"We'll look at our individual performances and team performance because, with where we want to go in the next six months and in the years ahead, that wasn't good enough.
"We'll work as hard as we can this week to be better, but it's a good indicator of where we are on this journey."
Ollie Lawrence has been ruled out of the climax to the Six Nations because of a hamstring injury, placing Manu Tuilagi in the frame to fill the vacancy at inside centre.