Are these the 21st century’s best January signings?

Are these the 21st century’s best January signings?

Virgil van Dijk (Southampton to Liverpool, 2018)Many felt the Anfield outfit had overpaid for the commanding centre-back but within months he was looking like a bargain. The Dutchman transformed the Reds' erratic defence and helped them to the UEFA Champions League final. This season, Liverpool have shipped just ten goals in their first 21 league games.