Will 2019 winners Portugal keep alive their hopes of a second Nations League Finals appearance?
When Czech Republic visited Estádio José Alvalade on matchday three, João Cancelo and Gonçalo Guedes were on target in a comfortable home win.
However, Fernando Santos’ side followed that up with a 1-0 defeat in Switzerland.
The only goal of the night at Stade de Genève coming after just 57 seconds, the fastest in Nations League history.
So, A Seleção sit second in this group, one point below Spain.
The two Iberian rivals meet in Braga on Tuesday, with Portugal needing to win this one first to ensure that is a winner takes all clash.
Czech Republic meanwhile are competing in League A for the very first time, but are yet to lose in Prague in this tier.
On matchday one, they beat Switzerland 2-1 before, three days later, Jakub Pešek and Jan Kuchta were on target in a 2-2 draw with Spain.
However, since then, Jaroslav Šilhavý's side have lost 2-0 twice, first, as mentioned, in Lisbon and then in Málaga last time out.
Nevertheless, the Czechs are third, one point clear of Switzerland, with those two clashing in St. Gallen on the final matchday.
Overall, it’s all to play for at both ends of the table, so will either claim a vital victory at Fortuna Arena?