A total of eight points from four games has left Portugal in second spot in the section, while Luxembourg are fourth, having picked up four points from their five fixtures thus far.
Portugal did not exactly fly out of the blocks in Group B as they were held at home by Ukraine and Serbia in their first two matches. Fernando Santos's side have won their last two in the section, though, recording a 4-2 victory away to Serbia before scoring five against Lithuania last time out.
Eight points from four matches has left the UEFA Nations League winners in second spot in the group - five points off Ukraine, who have played a game more. The section leaders host Lithuania on Friday night, and it would be a huge surprise if they did not manage to move onto 16 points.
As a result, there is a lot of pressure on Portugal to get things right against Luxembourg, who are fourth with four points. Friday's contest will actually be the 16th meeting between the two nations, with Portugal leading the head-to-head 13 wins to one, although they have not clashed in a competitive game since 2013.
Santos's side will travel to Ukraine in their next Group B fixture on Monday night, and it would perhaps be fair to assume that will be a decisive fixture. The Iberian nation will then welcome Lithuania and travel to Luxembourg in their final two matches in the middle of next month.
Portugal are, of course, the holders of the European Championships having triumphed in 2016. There are nations seemingly better equipped to land the 2020 title, although A Selecao das Quinas cannot be written off due to a certain Cristiano Ronaldo - now the second-highest international goalscorer of all time with 93.
Luxembourg have never qualified for the finals of a major international tournament, and the European nation face an uphill task to make it out of this section. Indeed, as mentioned above, they are fourth in the group with four points having won one, drawn one and lost three of their five matches.
Luc Holtz's side actually beat Lithuania in their first Group B game back in March, but have failed to win any of their last four, losing to Ukraine (twice) and Serbia in the process.
It was always going to be a tough ask to challenge the likes of Ukraine, Portugal and Serbia, but Luxembourg will be looking to win more than once during qualification for a European championships for the first time since 1996, which would certainly be a step in the right direction.
The omens are not exactly fantastic for the visitors, though, considering that they have lost each of their last eight internationals with Portugal since a 1-1 draw in a friendly back in October 1991. That said, they did beat the Iberian nation 4-2 during qualification for the 1962 World Cup.
It is difficult to see where the goals are going to come from on Friday night, however, as aside from Daniel da Mota with seven, no player in the current squad has netted more than five times for their country.
Portugal form: DDWW
Luxembourg form: WLDLL
There are not expected to be many alterations from the XI which started against Lithuania last time out, and Santos could in fact decide to send the exact same team onto the field.
Portugal possible starting lineup: Patricio; Semedo, Fonte, Dias, Guerreiro; Fernandes, Neves, Carvalho; Felix, Ronaldo, B Silva
Luxembourg possible starting lineup: Moris; Jans, Chanot, Gerson, Carlson; V. Thill, Sinani, Barreiro, O. Thill, Rodrigues; Deville
We say: Portugal 3-0 Luxembourg
It is difficult to back against Portugal on Friday night, especially with Santos's team needing a win due to Ukraine's form in the section, we fancy the home side to run out comfortable winners in Lisbon.