When Russia began its invasion of Ukraine on the morning of February 24, Darijo Srna was awoken at 6 a.m. by the sound of air raid sirens.

It was a noise the former international football star says immediately transported his "head and body" back to his native Croatia, where he lived as an eight-year-old when war broke out in what was then Yugoslavia.

So when his football club Shakhtar Donetsk was forced to leave Kyiv, the city that had been one of the team's many temporary bases since 2014, at the start of Russia's invasion, it was unfortunately a scenario Srna was all too familiar with.

The former Croatian international is just 39 years old, but he has already experienced three wars in his life; first in Croatia in the early 1990s, then in 2014 in Ukraine's Donbas region -- Shakhtar's real home -- and now across much of the rest of the country.

"It was not a nice memory," Srna, who is Shakhtar Donetsk's director of football, says of his childhood. "When I started to forget about that a little bit and enjoy my life, I heard the sirens again.

"I'm strong. I want to be strong, but sometimes is difficult because of everything, because you lost your home twice. In this moment, it's important to be positive, to be strong and to give a positive impression to everyone."

Srna -- who, along with the rest of the team, managed to escape Ukraine the day after Russia began its invasion -- has found his strength in helping those most affected by the war in Ukraine.

Shakhtar, where Srna is a club legend after playing for 15 seasons, has been homeless for almost eight years now, ever since fighting broke out between Russian-backed separatists and Ukrainian forces in 2014.

After retiring from professional football in 2019, Srna took up the role of assistant coach at Shakhtar before becoming the club's director of football.

He is acutely aware that his plight and that of the rest of the team is nothing compared to those fighting on the front line and has been helping to lead the club's effort in providing support for Ukrainian soldiers and refugees.

Shakhtar is currently in the middle of a European tour -- the 'Global Tour for Peace' -- during which they will play against a number of clubs to raise money for those caught up in the war.

"We cannot compare ourselves with the people of Ukraine," Srna tells CNN Sport's Don Riddell. "But we are a football team, we are football players and we are trying to do something we know how to do -- and that is play football.

"All the income we receive from tickets and from sponsors for these games we are sending to Ukraine for the children, for people who are in a very difficult situation.

"Together with our [club] president, Rinat Akhmetov -- who is still there helping Ukrainian citizens every day in different kind of ways, medicaments and everything -- we are now like one family and we are trying to do our best to help the citizens of Ukraine today in this difficult situation."

Before the opening match of the tour, a 1-0 defeat by Greek giant Olympiacos, Shakhtar's players wore t-shirts featuring the names of the places in Ukraine that had been most affected by Russia's assaults, including Mariupol and Irpin.

Shakhtar has since played games against Turkish clubs Fenerbahce and Antalyaspor and Polish side Lechia Gdansk, and has a match against Croatia's Hajduk Split scheduled for May 1.

There was a particularly moving moment in the match against Gdansk earlier this month when Dmytro Keda, a 12-year-old Ukrainian refugee, came on as a last-minute substitute and scored the winning goal.

Keda, who fled his hometown of Mariupol in Ukraine after spending three weeks holed up as Russian forces bombarded the city, was mobbed by players from both teams and was held aloft in celebration.

Shakhtar's head coach Roberto De Zerbi explained after the match that the decision to let Keda come on and score was "spontaneous."

So far, Shakhtar says the tour has raised 8.2 million Ukrainian hryvnia ($271,000), with around a quarter of the total already being transferred to Akhmetov's foundation in Ukraine.

"When I asked the Ukrainian players: 'Are you ready to play, for example, every second game, every third game?'" Srna recalls. "'The more games [we play], the more money for Ukrainians.'

"They responded to me: 'Darijo, we are Ukrainians. We can do everything.' And for me, that was a moment I will never forget.

"But this is the Ukrainian people. I arrived 19 years ago and they received me like part of their family from the first day and me and my family will never forget that. I've lived more in Ukraine than in Croatia. This is my home. Today I'm Ukrainian and everything we can do for them in these difficult moments, we will do. Believe me.

"I am proud that I lived there, that I played there, that I met them because they are people with a huge heart, always positive. They didn't attack anyone. They didn't want to take one centimeter of another country's land and they're heroes today. I'm so proud of them and me personally, I will be with them until the end."

Srna explains that the war has been particularly difficult for the younger members of Shaktar's squad to process.

Among them is the former captain of a club in Mariupol, who was invited to play with the team on their tour after he "lost everything" during Russia's ongoing bombardment of the city.

"First of all, it's good that they are young," Srna says. "In front of them, there is a long career and this can just make them stronger. I will say one thing: the most beautiful period of Croatia were the 10 or 15 years after the war.

"I believe that Ukraine will be united until the end and after the war we will be altogether. We will drink together, we will smile together, we will cry together. The most important thing will be peace in this moment."

On Tuesday the Ukrainian Premier League 2021-22 season was suspended due to the ongoing war. Shakhtar Donetsk and Dynamo Kiev were in first and second place on February 24, and will therefore qualify for next season's Champions League.

- By Don Riddell and Matias Grez, CNN