The 27-year-old is in his sixth season with the Bluebirds and was involved in their two most recent appearances in a Wembley final.
The south Wales club, with Dave Jones at the helm, suffered the disappointment of defeat to Portsmouth in the 2008 FA Cup final and then had to endure the agony of missing out on promotion to the Premier League when they lost to Blackpool in the 2010 Championship play-off final.
Former Aston Villa and Derby playmaker Williamson has no desire to go through those experiences again, and is determined to make it third time lucky as Malky Mackay's side look to upset the odds against the heavily-fancied Merseyside giants.
"Going to Wembley has not been too nice to us, obviously we lost to Blackpool in the play-off final so this is a good time to put things right and it's something we think we can do," Williamson said.
"That defeat was absolutely devastating, especially seeing Blackpool playing in the Premier League, that was horrible.
"It was the last game of the season and it was all you could think about for the next two months and it's something we want to put right.
"After all the hype it is good that the game is coming up and we want to do ourselves proud.
"It's a one-off game, league form goes out the window, it's a welcome distraction and we go to Wembley with not so much pressure on us to try and do well."
Whittingham admits that defeat to the Seasiders and last season's play-off semi-final reverse to Reading left him considering a move away from Cardiff.
But he revealed how speaking to new boss Malky Mackay, who has been handed a new three-and-a-half year contract, convinced him to stay on.
He said: "Last summer was difficult. Seeing Michael Chopra, Jay Bothroyd, Chris Burke and Craig Bellamy leave, but I spoke to the gaffer and he made the promise we would go for promotion again and we have.
"There were a couple of offers kicking about but once I spoke to the manager I wanted to stay."
Whittingham, who may lead Cardiff out at Wembley should Mark Hudson fail a late fitness test, will be a vital figure for the Bluebirds as he goes head-to-head with Steven Gerrard in the middle of the park.
Whittingham's influence and threat from set-pieces will be crucial if the Welsh side are to pull off an upset, but he says only focusing on the likes of Gerrard and Bellamy is a sure-fire recipe for failure.
"I have always enjoyed playing against really good players and hopefully I can step up to the plate," he said.
"But they have so many good players you can't really focus on individuals.
"We have to ride our luck, they will have chances but when we have ours we have to take them.
"Kenny (Miller) has scored some important goals and it would not surprise anyone if he scored on Sunday.
"We can't be in awe of the occasion, Liverpool are a massive club and have some great players but we have confidence in ourselves."
Carling Cup Final Facts
* Liverpool are playing in a record 11th League Cup final, having won the trophy a record seven times.
* The two sides have met only once in the League Cup in October 2007, which Liverpool won 2-1. From that team only Steven Gerrard, Jamie Carragher, Fabio Aurelio and Lucas Leiva remain at Anfield.
* In three cup meetings in their history Cardiff have the advantage thanks to two FA Cup victories. All three matches finished 2-1.
* Liverpool have scored in 43 of the last 44 League Cup matches - their only blank coming at Chelsea in December 2007.
* Victory for the Reds would make Kenny Dalglish only the third manager after Sir Alex Ferguson and Jose Mourinho, to win all three major domestic English trophies.
* All of Liverpool's League Cup final victories have come when the League Cup has been sponsored by a drinks manufacturer (Milk Marketing Board 1981-84), Coca-Cola 1995 and Worthington's in 2001 and 2003).
* Cardiff have reached their fourth major domestic cup final and will make their second final appearance in five seasons at Wembley.
* Only Kevin McNaughton, Peter Whittingham and Stephen McPhail remain from the team which lost the 2008 FA Cup final at Wembley.
* In a sequence stretching back to 1953 Cardiff have won eight of the last 10 meetings with Liverpool in all competitions, and of 29 games in all Cardiff have won 18 times to Liverpool's nine.
* Only five times previously has a lower-division side lifted the trophy - Norwich (1962), QPR (1967), Swindon (1969), Aston Villa (1975) and Sheffield Wednesday (1991) - with QPR, Swindon and Wednesday all defeating top-flight opponents.