Centre-backs - Virgil van Dijk & Dejan Lovren
Currently, the most expensive defender in the world, Virgil van Dijk started his professional career with Groningen and rose into the limelight while playing for Celtic in the Scottish Championship.
The Dutch international was signed by Southampton for £13 million in the summer transfer window of 2015 and he enjoyed a decent spell with the Saints. He played 67 Premier League games for Southampton and won the Southampton Player of the Season 2015-2016.
He joined Liverpool for £75 million in the January transfer window of 2018 and established himself among the best centre-backs in the world with the Merseyside-based club. He transformed Liverpool's shaky defence into one of the best in the league and played a key part in the Reds' unbeaten run in the league this season.
Liverpool has a special liking for Southampton players and five players on this list are currently playing for the Reds.
Dejan Lovren joined Southampton from Lyon in 2013 and immediately created a formidable partnership alongside Jose Fonte in the middle of the Saints' defence. He played 31 league games during his debut season and helped the Saints finish eighth in the Premier League.
However, his stay in the South coast didn't last for long and Lovren joined Liverpool for a fee of £20 million in 2016. He is currently an important part of the Reds' lineup and played a vital role in Liverpool's journey to the finals of the Champions League last season.