The Portuguese Football Federation (FPF) has quashed reports Cristiano Ronaldo threatened to walk out on Portugal's World Cup campaign.The 37-year-old was left on the bench for his country's 6-1 last-16 win over Switzerland by boss Fernando Santos, having reacted poorly to being substituted in the final group game against South Korea.He came on as a second-half substitute, but it was the first time that the former Manchester United, Real Madrid and Juventus forward was left out of a starting line-up at a major tournament since Euro 2008 and he held summit talks with Santos on Wednesday.Reports circulated on Thursday that during those discussions Ronaldo, who also acted petulantly during his final few weeks as a United player before the club terminated his contract, warned he would turn his back on his country and leave Qatar ahead of Saturday's quarter-final with Morocco.But the FPF has quickly shut down speculation and insisted Ronaldo has an "unquestionable degree of commitment to the national team".A statement read: "News released this Thursday reports that Cristiano Ronaldo threatened to leave the national team during a conversation with Fernando Santos, national coach."The FPF clarifies that at no time did the captain of the national team, Cristiano Ronaldo, threaten to leave the national team during the internship in Qatar."Cristiano Ronaldo builds up a unique track record every day at the service of the national team and the country, which must be respected and which attests to the unquestionable degree of commitment to the national team."Incidentally, the degree of dedication of the player most capped by Portugal was again demonstrated - if necessary - in the victory against Switzerland, in the round of 16 of the