Garry Monk has praised last season's performances from defensive duo Chico Flores and Ben Davies.
Flores signed for Swansea City from Genoa last summer, while Davies earned a place in the starting lineup for the first time following an injury to Neil Taylor.
The 34-year-old told the club's website: "Chico has done fantastically well. He is a very good footballer. Technically he is very good, and he has a different dimension to his game which he has brought into the Premier League.
"That can be very hard in your first season at a new club and league, but he has adapted very well. At the start of the season maybe he was a little rash and wild in certain games, but he controlled that and went on to flourish.
"Ben also flourished. He was my Player of the Season. To come from barely playing reserve football last season to being a Premier League regular is an unbelievable story. He was thrown in at the deep end, but he has taken his opportunity."
Swansea secured a place in the Europa League by winning the Capital One Cup in the 2012-13 season.