Williams wrote in the Daily Mail: "It's hard to explain how much I'm enjoying my football at Swansea. The club has been on an upward curve for a while and it's just so exciting to be part of that.
"We've had our difficulties, like losing Brendan Rodgers and big players like Joe Allen and Scott Sinclair in the summer, but a new manager and players have come in and done so well. It's crazy to think that we will be playing in a major cup final shortly.
"We obviously did well last season, but there was so much change that I don't think we really thought it would go this well. A few of the lads were laughing about it the other day, that here we are in a final and in the top half of the Premier League."