Cristiano Ronaldo’s replacement Goncalo Ramos marked his first Portugal start with a stunning hat-trick as Fernando Santos’ side hit Switzerland for six on their way to the World Cup quarter-finals.

The 37-year-old recently left Manchester United under a cloud and has at times cast a shadow over his team in Qatar, where his manager expressed unhappiness about his reaction to being substituted against South Korea.

Santos took the eye-catching decision to drop Ronaldo to the bench for the last-16 clash against Switzerland, with the Portugal talisman eventually coming onto a rapturous reaction with his side already home and hosed.

Cristiano Ronaldo, right, with coach Fernando SantosCristiano Ronaldo, right, watched his replacement steal the show (Mike Egerton/PA)

The veteran was the focus of every camera lens before kick-off but it was the 21-year-old playing in his place who left with the man of the match award, vindicating Santos in a 6-1 win that sets up a quarter-final against Morocco.

Ramos thrashed in a spectacular left-footed laser 17 minutes into his full debut, which Pepe added to with a powerful header as the 39-year-old became the oldest goalscorer in World Cup knockout history.

Portugal continued in the ascendancy after half-time as Ramos turned home from close range before playing in Raphael Guerreiro to open up a four-goal advantage.

The Benfica striker was disappointed to flick on a Swiss corner for Manuel Akanji to pull one back but became the first player in Qatar to score a hat-trick by coolly clipping over Yann Sommer.

The crowd chanted Ronaldo’s name and got their wish as he came on, with the star seeing a goal disallowed for offside before fellow substitute Rafael Leao curled home a beauty.

Ramos grinned at full-time as he left with the match ball for a treble that started with a stunner.

Goncalo Ramos, centre, scores Portugal’s first goalGoncalo Ramos scores Portugal’s first goal (Peter Byrne/PA)

Swiss goalkeeper Sommer looked over his shoulder in disbelief as the ball whizzed past him in the 17th minute after Ramos met a Joao Felix pass with a touch and unstoppable left-footed strike that flew in at the near post.

It was a brilliant goal that emboldened Portugal, who had some half-chances and survived a long-range Xherdan Shaqiri free-kick before extending their lead in the 33rd minute.

Bruno Fernandes sent over a corner and Pepe powered through to head home from six yards, sparking wild celebrations as Ronaldo and his fellow substitutes raced off the bench to join their team-mates.

Diogo Dalot cleared a Remo Freuler header after Portugal goalkeeper Diogo Costa spilled a cross but it was a rare chance for Switzerland, who had Sommer to thank for smartly keeping out Ramos before the break.

Half-time brought respite for Murat Yakin’s side, who were out of the contest within 10 minutes of the restart.

Dalot all too easily darted past Ruben Vargas and drove in a low cross that Ramos turned home from close range in the 51st minute.

Raphael Guerreiro celebrates his goalRaphael Guerreiro celebrates his goal (Martin Rickett/PA)

Within four minutes goalscorer turned provider, slipping through the overlapping Guerreiro to beat Sommer and put Portugal in dreamland.

There was a small bump in the road in the 58th minute when Ramos attempted to clear a corner, only to flick into the path of Akanji to turn in at the far post, but it was only ever going to be a Swiss consolation.

Portugal restored their four-goal advantage through a now familiar source in the 67th minute. Felix put Ramos in behind and the 21-year-old coolly dinked over the onrushing Sommer to complete his hat-trick.

It was a statement performance by Ramos and Portugal, whose manager delighted the crowd by bringing on star man Ronaldo in the 74th minute.

Cristiano Ronaldo prepares to come on against SwitzerlandCristiano Ronaldo prepares to come on (Mike Egerton/PA)

His entrance was met by a huge roar, as was his driven strike that rippled the back of the net in the 84th minute. Ronaldo, though, looked straight to the linesman and saw the flag raised for offside.

Breel Embolo went close with an audacious overhead kick before that but Switzerland were just waiting for the final whistle by that point.

Perhaps that is why substitute Leao had the space and time to bend home a brilliant sixth in stoppage time.