One the tournament's star performers so far picked up where he left off after his hat-trick against Spain in Portugal's opening 3-3 Group B draw, heading Fernando Santos' men into an early lead with a goal that moved him to 85 worldwide goals - one ahead of the legendary Ferenc Puskas in the all-time standings.
Portugal have no such concerns and will seek to win the group in their final game against Iran, while Morocco face Spain, both on June 25.
American official Mark Geiger is at the centre of the controversy with Morocco's coach, Herve Renard, also unhappy with a number of decisions made.
But his plans were torn apart within minutes at the Luzhniki Stadium as Ronaldo wriggled free of the imposing Da Costa to bury an unstoppable header past a helpless Monir El Kajoui.
The Real Madrid forward threatened a second soon after, swivelling on the edge of the area and scuffing just wide after a powerful run from left-back Raphael Guerreiro.
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However, BTP later tweeted: "Enquiries continue but we do not believe this to be terror related at [this] time". Police have evacuated a Tube station during rush hour after an "explosion" left a number of people injured.
The incredible reaction in Walkabout Sheffield after England's last-minute victor against Tunisia
He has scored 135 goals in the past four seasons, including 41 last term as Tottenham finished third in the Premier League . England were singing God Save the Queen before their World Cup opener with Tunisia .
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One young fan said: "I was alright until Beyoncé and Jay sang Forever Young in tribute to Grenfell and then I lost my s-t". According to Pitchfork , rumors have always been around about the Carters teaming up for an album .
Morocco did well to insert its presence in the match following the early goal, but various chances from Medhi Benatia and Hakim Ziyech weren't enough to break past Portugal goalkeeper Rui Patricio.
Morocco's Nordin Amrabat has slammed the lack of use of VAR during his side's 1-0 defeat to Portugal. He could not get the ball up and over a solid wall of defenders on either occasion.
Luis Suarez marked his 100th global cap by sending Uruguay into the last 16 of the World Cup as the striker benefited from some poor goalkeeping to eliminate Saudi Arabia with a 1-0 win.
The lively Ziyach nipped past Fonte in the closing minutes but found Pepe standing in his way, with Benatia hammering over one final chance to seal Morocco's fate.
Depending on the result of their last group game against Russia, Uruguay will take on either Spain, Portugal or Iran, who are still on course in Group B for a place in the quarter-finals.