Lauren Blud feels as if she is having a panic attack whenever she steps on to the pitch before a game. But as soon as the referee’s whistle sounds, she thinks about nothing else but helping Wales win.

“It means the world to me to be playing for my country,” said Blud. “I’m so proud. Everything else that is going on in my life goes out of my mind.”

Blud is one of 500 players from around the globe playing in the Homeless World Cup, which has been running for a week in Cardiff and comes to a climax on Saturday.

The striker for Wales women said the team and the competition were giving her a sense of meaning that she lacked when she lived in insecure accommodation and, for a while, on the street.

Facebook Twitter Pinterest Lauren Blud scores one of five goals for Wales women against Belgium. Photograph: Gareth Phillips/The Guardian

“I didn’t think I was worth anything,” she said. Her future is looking much brighter. During the week-long tournament she has heard she is going to move into a flat of her own and she is now planning to do her football coaching badges. “Life is looking good,” she said before jogging off to play Belgium – and banging in five goals.

Players taking part in the competition include people who have been homeless within the last year, asylum seekers, sellers of street papers and those in drug or alcohol rehabilitation.

Cardiff 2019 is the 17th edition of the competition, which has given thousands of players the chance to travel, meet new friends and perhaps get a glimpse of a better future.

The games are fast and furious. The teams play four-a-side on a small pitch and each half lasts just seven energetic minutes. The players love it and it is a great spectacle. The temporary stands in Bute Park, where many of Cardiff’s rough sleepers pitch tents all year round, have been packed.

Facebook Twitter Pinterest Juan Jesus Rios of Mexico, a former drug dealer, was badly burned when he carried out an arson attack. Football helped get his life back on track. Photograph: Gareth Phillips/The Guardian

And the competitors have amazing stories to tell. Juan Jesus Rios, for example, was living on the streets of Ciudad Juárez in Mexico when he was 14. He said he used – and dealt – drugs, and suffered terrible burns when he carried out an arson attack. He got his life back on track after finding the organisation Street Soccer Mexico, which selects and trains his country’s team.

“I feel an enormous passion and happiness every time I kick a ball. It’s one of the things I love most in the world,” he said.

The Mexico men’s team are the current holders of the World Cup and won their first eight games in Cardiff. “It makes me proud to be here,” he said.

Countries select in different ways. Some pick the best players; others choose those they feel are most deserving and would benefit most.

For the Dutch defender and goalkeeper Dennis Koopmans, the event is as much about about learning as playing football. “I stand a little bit with one leg out of society and I want to stand in society with both legs again,” he said. “Everyone here has some baggage and I have the feeling that everyone is equal, everyone understands each other. It’s cool.”

Facebook Twitter Pinterest Dennis Koopmans: ‘Everyone here has some baggage and I have the feeling that everyone is equal.’ Photograph: Gareth Phillips/The Guardian

Mel Young, the co-founder of the Homeless World Cup Foundation, said one of the best games he had seen so far in Cardiff was a clash between Russia and Poland. It was 6-6 with seconds to go when a Polish player lashed a shot towards the goal. An instant before the ball crossed the line the referee blew for full-time. Russia won on penalties.

Young said for him the tournament was all about change. “Since 2003 we have witnessed transformations in the lives of thousands of players,” he said. But it was also about changing the perceptions of those who came to watch. “These are not homeless people when they play – they are footballers. As soon as the games kick off you forget they’re homeless.”

The actor and activist Michael Sheen ploughed his own money into the event to save the tournament when it looked as if it was in difficulties and might not go ahead.

“There were 500 people who suddenly weren’t going to have this life-changing experience. I know it can be a catalyst for change,” he said. So he dipped into his own bank account and bankrolled it, arguing that he would be able to find work to recoup his losses.

Facebook Twitter Pinterest ‘This can change people’s perceptions’: Michael Sheen bankrolled the tournament. Photograph: Gareth Phillips/The Guardian

Sheen said the sight of the Bulgarian goalkeeper sobbing inconsolably after a defeat would live long in his memory. “That was real passion,” he said. His imagination was also fired by a young woman from Northern Ireland celebrating wildly. “It looked as if she hadn’t scored many goals before. But she had now scored a goal for her country.”

He has also been impressed by the spectators who have pledged to try to do something to help, including the children who have promised to do something as simple as smiling at the next person they see on the street.

“Something like this can change people’s perceptions,” Sheen said. “The idea that the homeless are this block to be pitied or given charity or to be judged or stigmatised is blown apart when you’re watching them playing and cheering them.”

Over on pitch one the Welsh men’s team were soundly beaten by an excellent Egypt side. The men’s coach, Wayne Ellaway, still came off smiling, especially after Wales grabbed a last-minute consolation goal. “That gave the crowd something to cheer,” he said.

Facebook Twitter Pinterest The Mexico women’s team resting after a match. Photograph: Gareth Phillips/The Guardian

Ellaway admits to having lived a troubled life but his fortunes have been turned round by playing for and now coaching the Wales team. “This is a way of trying to make amends to my family, friends and community for the pain I have put them through.”

He said he saw vulnerable people changing into proud adults as they trained and competed. “The change is phenomenal,” he said.

The venue, Bute Park, is particularly poignant for Ellaway. This was one of the spots he used to pass the time at his lowest point. “I used to walk around this place in despair, not knowing where to go, what to do. Now I’m coaching Wales here – it’s amazing.”