Two goals in five second half minutes from Robin van Persie and Andriy Arshavin turned the tide for the Gunners after David Villa had given the Spanish giants a first half lead, and Redknapp believes Arsene Wenger’s decision to play a deeper defensive line after the interval made a decisive difference.
Writing in his Sky Sports column, Redknapp said: "You would also expect the same from Barcelona in the second leg at the Camp Nou. I have to say I didn't think Arsenal would lose on Wednesday but you still have to congratulate them on winning that game.
"Especially if, like me, you thought they were playing suicide football in the first half! I sat watching that and could not believe my eyes. Everybody had been talking about stopping Barcelona by sitting back and letting them pass that ball around in front of you - like Inter did last year - as being the best way to handle them.
"Well I sat and watched Arsenal play offside with such a high line, it was ridiculous! Let's be honest, if Lionel Messi's goal had not been ruled out when it should have stood, they would have been 2-0 down and in dire, dire straits.
"But in the second half, once they got Samir Nasri more involved, Arsenal showed how you can beat them. Barcelona do press and press very well, but they do it high up the pitch. If you try and play between their midfield and back four they suffocate you, simple as that."
Arsenal caused the Barcelona defence far more problems in the second half, with the likes of Cesc Fabregas, Samir Nasri and Andriy Arshavin all becoming more influential.
Redknapp believes this was a result of the Gunners’ willingness to commit more men forward after the interval, and he also believes this strategy could also work well in the second leg at the Camp Nou as they seek to protect their slender lead.
"What Arsenal did after the break was get players breaking between those lines. We saw it with that fabulous second goal; Jack Wilshere to Cesc Fabregas and then all of a sudden Nasri was beyond the midfield and attacking the back four. And for all their brilliance, I do think that is one area where Barcelona do have a weakness.
"If they don't win that first ball and you are brave, they can be got at - and Gerard Pique will be missing in the second leg which makes them even more susceptible. And I do think they are a better side than 12 months ago."
By Liam Twomey
