Spurs were two minutes away from an embarrassing semi-final defeat to Burnley, letting slip a 4-1 lead from the first leg and trailing on away goals until Roman Pavlyuchenko and Jermain Defoe struck.

More than a month later and Spurs are not clear of Barclays Premier League relegation worries but they were in much deeper trouble when they travelled to Turf Moor and losing that tie would have impacted on their survival bid.

"It would certainly have made it very, very difficult for us to have lifted ourselves," he said. "The shame of it all, of being 4-1 up and going out the competition.

"That was as angry as I have been since I have been here. I was very, very low. Imagine how low we would have been if we had gone out.

"If we had gone out we would have been in desperate trouble because I don't know how we would have recovered from that."

Redknapp described the league win over Hull last Monday as the most important since his arrival at the club and the seriousness of Spurs' league position is illustrated by the players staying in a hotel on Sunday.

Regardless of whether they win or lose, they have an important match against Middlesbrough on Wednesday and will not be partying until the early hours as they did when they won the trophy last season.

"We are going back to the hotel we are staying at before the final and we are going to prepare for the game on Wednesday, another massive game against Middlesbrough," Redknapp said.

"We wont have any time for it. Grab-a-granny night is it? I'm too old for that now."

The final will be another clash against United boss Sir Alex Ferguson, a good friend but a fierce competitor who Redknapp has famously beaten in the FA Cup with Bournemouth 25 years ago and Portsmouth last year. He also denied United the title in 1995 when his West Ham side earned a point at Upton Park.

There is nothing but respect from Redknapp towards Ferguson. They talk to each other about players, with Ferguson recommending Sulley Muntari after seeing the Ghana midfielder on trial at United before he joined Pompey.

Redknapp feels United are the best team in Europe but was puzzled why some bookmakers are already paying out on them winning the domestic treble.

"It's disrespectful to everybody, for the teams in the FA Cup still," he said. "We have players who can go there on the day and play very well."

Redknapp will assess Ledley King's knee before deciding his starting XI, while Jamie O'Hara has forced his way into contention after recovering from hip and groin problems.

O'Hara would compete with David Bentley for a place on the left flank. O'Hara has been praised for his attitude recently, while Bentley's form has been patchy.

"I had one meeting when I told them all exactly what I thought about them and how they come across to me, and I was open with them," Redknapp said.

"I told David I thought he could do better. He's got terrific ability and he did respond to that with a couple of good performances."

In goal, Heurelho Gomes will start as Carlo Cudicini is cup-tied.

Redknapp was furious in the dug-out when Gomes dribbled around a Shakhtar Donetsk striker during the UEFA Cup clash on Thursday.

"If he lost the ball, he would have been killed really," Redknapp said. "It was crazy. It is that mentality of coming from Brazil, where they throw the ball out to everyone, and the left-back is not closed down by the winger."

Another certainty is playmaker Luka Modric, who Redknapp builds his team around going forward.

"Modric did it for Croatia at Wembley, so for him to be going back is good," Redknapp said.

It will be his first team, as Redknapp cannot afford to blood youngsters in the same Ferguson does.

"Our young-uns are youth-team players," Redknapp said. "We haven't really got a group of 20-year-olds at this club.

"(Danny) Welbeck was a real threat up at Old Trafford against us. He'll probably have (Wayne) Rooney and (Carlos) Tevez up front. They'll still be strong."