The hosts fell to a 1-0 defeat to Spain on Thursday night, while Fernando Santos's side eased to a 2-0 success over the Czech Republic.
Match preview
Switzerland's chances of progressing to the Nations League Finals were always considered to be remote, but a dissatisfactory set of results this weekend could seal their fate in that regard after a damaging start to the new cycle.
Returning to home comforts after away defeats to the Czech Republic and Portugal, Switzerland hosted Spain on Thursday night but once again flattered to deceive on the attacking front, as Pablo Sarabia's effort settled the contest in La Roja's favour.
Murat Yakin's men unsurprisingly sit rock bottom of the rankings as one of only two sides across the four League A groups yet to pick up a point - the other being Wales, who have played a game fewer - and they cannot rise any higher before the month is up.
Switzerland have been ever-presents in League A since the Nations League came about but are surely fearing for their safety in the top tier now, and Yakin's side could have done without this hit to the confidence before they test their mettle in Qatar.
It is now four defeats and a draw in their last five matches for the Rossocrociati, who have only won one of their last five Nations League games on home soil and could desperately use a summer of rest and recovery before September's fixtures roll around.
With one foot already in the finals of the 2022-23 Nations League, Portugal can steer further clear of Iberian counterparts Spain at the top of the rankings this week and were in no mood to suffer any scares against a resilient Czech Republic side last time out.
First-half strikes from Goncalo Guedes and Joao Cancelo put the tie to bed as the Selecao continue to ramp up preparations for the 2022 World Cup, although coach Fernando Santos was frustrated not to see his side make their dominance count for more goals in midweek.
Nevertheless, the Selecao hold a two-point lead over Spain at the top of the rankings, although La Roja will expect to make it past the Czechs on their own turf, so the onus is on Portugal to avoid a shock result against the section's resident whipping boys.
While Switzerland's most recent five games have seen them post four defeats and a draw, Portugal have instead registered four wins and one stalemate, and Santos's side have not suffered a single defeat away from home in the Nations League since its inception.
Cristiano Ronaldo was at the double as Portugal thumped Switzerland 4-0 only a week ago, which marked a third win on the bounce for the Selecao in this fixture, although their most recent trip to Swiss turf ended in a 2-0 loss during a 2018 World Cup qualifier.
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Team News
Switzerland will have defender Fabian Schar back from a one-game ban for the visit of Portugal, which could therefore force Eray Comert to accept a place on the bench as the Newcastle United man partners Manuel Akanji.
Nico Elvedi missed out entirely in midweek and remains doubtful alongside Ruben Vargas, but Yakin should not hesitate to make a number of alterations either way.
Noah Okafor and Renato Steffen can freshen up a shot-shy attack which has only scored one goal in the Nations League so far, while Djibril Sow is in line to displace Michel Aebischer in the middle.
As for Portugal, none of Ricardo Horta, Domingos Duarte or Matheus Nunes were in the matchday squad for the win over the Czechs, but the trio will hope to earn some minutes here after a taxing two-week period.
Santos has no injury or suspension concerns whatsoever but may be tempted to hand veteran Pepe a rest, which could see David Carmo finally earn his debut for the national team.
It would not be a surprise to see Cristiano Ronaldo demoted to the bench either, especially after he picked up a yellow card on matchday three, as Andre Silva battles to return to the forward line.
Switzerland possible starting lineup:
Sommer; Lotomba, Schar, Akanji, Rodriguez; Freuler, Sow; Steffen, Shaqiri, Okafor; Embolo
Portugal possible starting lineup:
Patricio; Dalot, Pereira, Carmo, Mendes; B. Silva, Moutinho, Fernandes; Jota, A. Silva, Leao
We say: Switzerland 1-2 Portugal
Switzerland have seemed devoid of ideas on the attacking front for large periods of their Nations League campaign so far, but the prospect of sweeping Portugal changes could play into the hands of Yakin's side in front of the home crowd.
Then again, Portugal need no lessons in finding the back of the net themselves, even if Santos makes a big call regarding Ronaldo, and the Selecao should retain their healthy lead at the top before jetting off for their well-earned holidays.