The Gunners will be looking to stay in the Premier League title race after being handed a footballing lesson by a Lionel Messi-inspired Barcelona in the Nou Camp.
The battle-weary and injury-hit Gunners must now lift themselves for the final five matches of the domestic campaign having seen their European dreams shattered after a 4-1 defeat in Spain.
Arsenal keeper Almunia, however, believes a short trip across north London to face their arch-rivals at White Hart Lane could be just the sort of encounter Arsene Wenger's men need to keep things in perspective.
"We are down and disappointed, but we have to accept that Barcelona were better than us in both legs and now we must focus on winning the Premier League," the Spanish goalkeeper said.
"Tottenham are playing for a Champions League place and it will be a very tough game - no matter when we play or what we are fighting for, a derby match is special.
"Everybody has played at Tottenham's stadium and we won't be surprised by the hostility.
"We have played against them many times, so we know their football and support."
In the build-up to the Champions League quarter-final second leg, Wenger had talked of the great strength of character his squad have shown throughout a campaign which has seen them written off time and again, only to come out fighting - and indeed Arsenal had taken a shock lead at the Nou Camp through Nicklas Bendtner.
However, while eventually the absence of key men like captain Cesc Fabregas, William Gallas, Andrey Arshavin and Alex Song proved too much to overcome against the Catalans, Almunia is in no doubt the squad have what it takes to raise themselves for one final push as Arsenal aim to overhaul Chelsea and Manchester United with just three points separating the challengers.
"We are in a good place in the Premier League and we have to show big character as we have done already in big moments," he said.
"We have to believe we can still win a trophy - if not, then we should go home and forget the season.
"At least we are in the league fighting for the title and that is what we want.
"We want to play the last few games where anything is possible, otherwise we would be very disappointed and bored.
"It is a completely different game against Spurs and I think we will be okay for that match."
Almunia had performed heroics in the first leg to prevent Barcelona from being out of sight before half-time, but had little chance to stop any of Messi's well-taken efforts at the Nou Camp.
The 32-year-old accepts sometimes there is just nothing you can do against a player of the Argentinian's quality.
"After we scored, Messi woke up and had a great night," said the Arsenal keeper, who was beaten by an exquisite chip as Messi completed his hat-trick just before the break.
"He is used to having these kind of games and when you have a player like this, it is difficult to stop him.
"You try to guess what he is going to do and anticipate him, but his skills are great and he can do anything at any moment."