Portugal will aim to progress to the quarter-finals of the World Cup for just the third time when they tackle Switzerland in Tuesday's last-16 clash at the Lusail Iconic Stadium.

Fernando Santos's side sealed progression from Group H after getting the better of Ghana and Uruguay, although they succumbed to a 2-1 loss to South Korea in their most recent group game.

Not since 2006 have A Selecao managed to reach the last eight of football's biggest global event, but optimism is high surrounding Portugal's chances of breaking new ground in Qatar.

Here, Sports Mole looks at three reasons for Portugal to be confident of making it through to the quarter-finals with victory over Switzerland.

Goalscoring prowess

Finding the back of the net at the World Cup has been customary for Portugal over the past eight years, and many have tried and failed to keep a clean sheet against Santos's charges since the 2014 tournament.

Portugal were memorably put to the sword 4-0 by eventual winners Germany at the 2014 World Cup, but they have since scored in each of their last nine World Cup matches - racking up 16 goals in total.

Santos's side head into the knockout stages after striking six goals in three games in the group phase, netting three against Ghana before putting two past Uruguay and another one past South Korea, which largely made up for their defensive frailties in the early days of the competition.

Furthermore, Portugal have only failed to make the net ripple in four of their last 20 matches across all tournaments, and a shortage of attacking options is one that Santos rarely has to face as he prepares to meet a Switzerland side with just one clean sheet in six.

First blood

When Portugal score first at the World Cup, they tend to prevail, and Santos's side have made a habit of drawing first blood in the tournament over the past couple of editions.

The 2016 European champions have scored the opening goal in eight of their last nine matches at the World Cup, with the exception being their 2-1 last-16 defeat to Uruguay - whom they got revenge over this year - in the 2018 World Cup last 16.

Ricardo Horta made the net bulge early doors against South Korea, although the Asian nation ultimately came back to become the first team to ever beat Portugal at the World Cup after conceding first.

Nevertheless, Portugal boast an imposing record of 15 wins and three draws from their other 18 World Cup games in which they have scored the opening goal, meaning that Switzerland's task will become all the more mountainous should they fail to keep their defence watertight.

Switzerland defensive doubts

Switzerland would hope to be blessed with a fully-fit defence ahead of a clash with Portugal, and while that should be the case, Murat Yakin does have some concerns over two of his mainstays.

Number one goalkeeper Yann Sommer and Borussia Monchengladbach teammate Nico Elvedi both came down with a cold before the Rossocrociati's clash with Serbia, and neither were able to play a part in the match.

Yakin affirmed that the duo's absence did not concern him as Gregor Kobel and in-form Newcastle United centre-back Fabian Schar deputised, but the pair were part of a backline who conceded twice against Serbia after the Sommer and Elvedi-led defence kept Brazil at bay for 83 minutes.

Both players will hope to recover from their illnesses in time to line up from the first whistle here, but Yakin could do without that uncertainty before meeting a prolific Portugal, especially with Sommer saving an impressive 24 of the 93 non-shootout penalties he has faced in his career.

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