Fernando Santos' side, who are aiming for a second successive summer of success following their triumph at the European Championship last year, amassed seven points from their first three fixtures to advance in first place. They were, in truth, far from their best against Mexico in their opening encounter, but strong performances against host nation Russia (a 1-0 win) and New Zealand (a 4-0 win) will have increased the levels of confidence in the camp. Portugal will fear no-one heading into the knockout stage, particularly after claiming their first piece of silverware at senior level 12 months ago.
Chile were many people's favourites to lift the trophy before the tournament began, and they too avoided defeat in the group stage. A return of one win (2-0 against Cameroon) and two draws (in clashes with Germany and Australia) was perhaps less than what was expected, however, and it will be interesting to see whether they are able to assert themselves on this semi-final. This is the fourth consecutive summer in which they have participated in an international tournament and there is some concern that fatigue is starting to have an adverse impact on the team's displays.
Santos' selection against Mexico took many by surprise, but the former Greece head coach now looks to have settled on a favoured starting XI. Having spent much of his international career cutting infield from the left flank, Cristiano Ronaldo is now being employed alongside Adrien Silva through the middle in a 4-4-2 formation. Bernardo Silva provides creativity from his starting position on the right, with William Carvalho and Danilo Pereira set to battle it out for the remaining central midfield spot alongside Joao Mario. At the back, ageing centre-halves Pepe and Bruno Alves can be vulnerable to pace, which is one of the reasons why Santos is likely to instruct his men to defend close to their own goal.
Chile will line up in a 4-3-3 configuration, with an emphasis on pushing players forward in possession and pressing high up the pitch when control of the ball is lost. Playmaker Marcelo Silva will probably return to the side in place of either Francisco Silva or Charles Aranguiz in midfield, while Jose Pedro Fuenzalida is vying to keep his place alongside Alexis Sanchez and Juan Vargas in the forward line. Manchester City goalkeeper Claudio Bravo, meanwhile, should get the nod ahead of Johnny Herrera between the sticks.
Taking everything into account, it is probably worth putting some money on a Portugal victory at the Kazan Arena on Wednesday night. Chile are capable of some stunning football on their day, but the European champions will look to make life difficult for Pizzi's men and could pick them off on the counter-attack. Both teams will probably find the back of the net, but it would be sensible to come down on Portugal's side when picking a winner in this one.