Portugal's qualification for the round of 16 at the World Cup brought a sense of relief rather than euphoria, as coach Roberto Martinez's team advanced after defeating Croatia but still struggled to meet the expectations that have accompanied them since the start of the tournament.

The team, led by Cristiano Ronaldo and considered one of the top contenders for the title, appeared more practical than fearsome to opponents, blending quality with inconsistency, which left them in second place behind Colombia in their group after two draws in three matches.

Their hard-fought 2-1 win over Croatia secured their place in the round of 16, but it failed to ease concerns among fans in Portugal, as the performances of key players such as midfielders Vitinha and Bruno Fernandes came under scrutiny.

Ronaldo scored a penalty, his first goal in knockout stages of a World Cup, postponing by at least one match what could be his farewell to the Portuguese national team, after his sister indicated in an interview that he would retire from international football after the tournament.

However, the 41-year-old's role as an almost untouchable figure remains a source of concern for some fans and sections of the Portuguese media.

Ronaldo was substituted in the second half of the match against Croatia and appeared to cast a displeased glance at Spanish coach Martinez as he left the pitch, adding another dimension to the debate over how Portugal should use their captain in the knockout stages.

"The national team is a group of players still striving to become a cohesive unit," wrote Portuguese newspaper Record in a headline. This quest for cohesion now faces a tough test.

Portugal will face European champions Spain in the round of 16 on Monday, a match that offers Martinez's side a chance to turn a journey marked by doubts into one with genuine momentum.