Cristiano Ronaldo was grabbed by an overenthusiastic fan who invaded Portugal's training field as the team finalized preparations for its Euro 2024 campaign.

With Portugal's Group F opener not until Tuesday in Leipzig, head coach Roberto Martinez staged an open training session in the German city of Gutersloh that allowed the public an early glimpse of Ronaldo and his colleagues.

However, with more than 50,000 supporters having applied for the 6,000 available tickets, scenes soon turned chaotic.

Midway through the session, a fan jumped over the barriers and sprinted onto the field. After slipping past two advancing security guards, he forcibly hugged Ronaldo before being apprehended almost immediately. Ronaldo allowed the fan to take a selfie with him but then raised his arms to appeal for calm from the crowd.

Later, several spectators jumped onto the pitch and ran towards the players, with Portugal goalkeeper Jose Sa tackling one of the intruders before he could advance further.

Martinez has spoken of his wish to tap into the strong support Portugal is likely to receive during the tournament, in large part due to Ronaldo's lingering popularity as he enters what is expected to be the final stages of his career.

Friday's scenes may cause Martinez to rethink future public practices, though Ronaldo did not appear unduly troubled by the attention, apart from the fact that it briefly disrupted the session.

Portugal was the only nation to win each of its 10 games in qualifying. They come in as one of the favorites to win the tournament and will take on Czech Republic (June 18 at 3:00 p.m. ET on FOX and the FOX Sports app). Ronaldo is likely to play a prominent role, despite opinions from some pundits that he would be more effective off the bench.

The 39-year-old will be playing at his sixth European Championship, and already holds the record of most international appearances by any male player with 207, and most goals with 130.

"I know I don't have many years of football left," Ronaldo told reporters this week. "It is a gift to play year after year after age 35. I am 39 and every year is about enjoying things.

Ronaldo moved to Al-Nassr of the Saudi Pro League 18 months ago and appears to have been rejuvenated by the move, after his last spell in Europe with Manchester United fell apart amid acrimony and poor form.

He was superb in qualifying and holds high hopes that he can add another Euros title after winning the event in 2016, albeit with getting injured and missing most of the final against France.

"I believe that this generation deserves to win a competition of this magnitude," he said. "Semifinals? I hope we can go further.

"We have to go step by step, live in the moment, be calm, work as well as we have until now, believe that it is possible. We know it's a short competition, but the team is ready."

Martin Rogers is a columnist for FOX Sports. Follow him on Twitter @MRogersFOX and subscribe to the daily newsletter.

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