Swansea pulled off a huge result at Stamford Bridge two weeks ago and the Betfair market makes them firm favourites to qualify - Michael Laudrup's men are 1.42/5 to make it to Wembley.
A professional performance will be enough to get them through, but the first 45 minutes are going to be crucial; any early goals for the opposition and the pressure will be on. The Blues, and Rafa Benitez for that matter, have been here and got the t-shirt and they will seize on any nerves in the home camp.
Teams can get very anxious on these occasions and that can be toxic. Believe me, fear and football do not mix.
But while I won't be taking a short price on Swansea to qualify, I do feel they will get through and that reflects the faith I have in the manager.
This has been a fantastic first season for the former Danish international with plenty of notable results in his short tenure at the Liberty Stadium. His team are decent in defence, creative in attack and ninth place in the Premier League does not flatter them - they're very much in contention for a European place.
Laudrup reminds me of Dennis Bergkamp. He was a remarkable player too, and looks as though he brings an icy calm to the dugout and dressing room. He is a quiet, reassuring presence and with a manager like him at the helm I don't think the Swans will lose their cool on Wednesday night. It will be interesting to see how they play, given the 2-0 lead, but I can't see them changing their passing game.
Chelsea come into the game off the back of a heartening defeat of Arsenal, finally ending a short run of terrible home results under their interim manager.
To be fair, the Benitez effect is not so strong on the road and some key players are coming to form. Opta tell us that Juan Mata, a scorer on Sunday, has scored two goals and assisted four more in just five League Cup appearances for Chelsea while Frank Lampard has three in his last five appearances. The England man has won everything with the Blues and would be my bet in the to score market.
The first 45 minutes are absolutely vital to both sides and I envisage a tight, cagey affair up to the break. It could go goal crazy in the second 45 minutes and I wouldn't be afraid to get involved in-play on that basis.
But when all is said and done it's Swansea who will be making the Capital One Cup final to cap a fantastic first season under Laudrup.
Back the halftime draw @ 2.56/4
Back more goals in the second half @ 2.26/5
Back Frank Lampard to score @ 4.03/1