Manchester United superstar Cristiano Ronaldo has taken to social media to apologize for his "outburst" after a widely shared video that appears to show him smashing a fan's phone following his side's stunning defeat at relegation-threatened Everton on Saturday.

The incident happened when the 37-year-old headed for the tunnel at Goodison Park after the full-time whistle. Eyewitnesses reports published by several British media outlets said Ronaldo knocked a supporter's phone out of his hands, and it fell to the ground.

"It's never easy to deal with emotions in difficult moments such as the one we are facing," Ronaldo said on Instagram. "Nevertheless, we always have to be respectful, patient and set the example for all the youngsters who love the beautiful game."

"I would like to apologize for my outburst, and if possible, I would like to invite this supporter to watch a game at Old Trafford as a sign of fair play and sportsmanship," the Portuguese player added. 

United also issued a statement later in the day, saying they were aware of "an alleged incident" after the Everton game and the club "will cooperate with any police inquiries." 

It was a bad day for both Ronaldo and United, as Saturday's defeat left the English giants seventh in the Premier League, and they look increasingly unlikely to qualify for the Champions League next season.

"It's a disgrace from us, to be honest; we should win the game," United goalkeeper David de Gea said at a press briefing. "We don't create; that's the problem. We don't even create proper chances to score. I don't know what to say, to be honest."

"We're not good enough, that's for sure. It's going to be very difficult now to be in the top four," he fumed.