Sergiy Stakhovsky was in the middle of a holiday when he got a call from his parents.
There were explosions outside of their house.
Russia invaded.
When he switched on the news, he didn't sleep or think for three days.
He tells the BBC that he was trying to understand where his family were and how bad it was.
He was playing in the Australian Open qualification a month before. He decided to end his tennis career at the age of 36 after a defeat in the Australian Open. He was ranked 31 in the world in 2010. He beat Roger Federer at Wimbledon in the quarter-finals, ending the champion's run of 36 consecutive Grand Slam quarter-Final appearances.
He knew what he would do next.
He brought his family back to Hungary. His wife asked what he was going to do.
It was not the answer she wanted to hear, and she got upset.
I played Davis Cup with pride for almost 17 years, so I don't see how I could stay out of what's happening in my country.
I sneaked out. The kids were watching cartoons and reading. The youngest one asked me where I was going and I said I would come back.
After picking up some gear in Slovakia, he drove to the border with Ukraine. People were leaving. The children were standing in the cold.
He met up with a friend and they drove towards Lviv. He went to meet his brother and father in Kyiv the night before. He planned for his mother to escape along with his brother's wife and two daughters.
He was assigned to a military unit and was stationed in Kyiv, trying to help as much as he could. The enormity of the situation began to sink in. He did not have any military training.
He says that they wanted to use that time to the maximum because they didn't know when they were going to start shelling.
We all slept next to the Kalashnikov. We need to be ready when there is a strike.
He was doing press interviews to get the attention of the people. He wanted to counter the Russian narrative about his country.
He was always going to the shelter because of the air raids. He went to see the horrors of the war, but it was an emotional time for him.
The Russians occupied the town of Bucha for a month at the beginning of the war. There is evidence that people are being tortured and murdered.
The world has seen images of the situation there, but only a small reflection of what happened. He wasn't sure what he would do if he had to fight. That changed after Bucha.
The way they did it is morally reprehensible, he says.
The people who lived there did not deserve it. They weren't part of the war. They did not want to participate. They didn't have the chance to live and were just civilians.
I would not hesitate. I know what I will do if I see a Russian soldier.
Since the invasion, there has been a lot of discussion about how to react to Russian athletes and whether they should be banned from competing internationally. Tennis has different approaches.
In the first weeks of the conflict, a Russian tennis player wrote "no war please" on a TV camera lens after winning a match. The world number two spoke about promoting peace. A new Russian law can lead to up to 15 years in jail for spreading fake news about the military. Most Russian sports people have not spoken since.
Russian athletes will not be allowed to compete in the Wimbledon tournament this summer. It was met with a mixed reception.
He believed that the Russians would go out and protest once they saw what the army was doing.
That didn't happen. Nobody showed up. Few people came to protest. There were no people.
I stand behind it.
The man has been able to return to Hungary. He explained to his children what he was doing in Ukraine during a brief visit home.
He says that he and his wife talked it through and that he feels better about himself.
I left three kids and a wife I adore and went to defend my country and my family. There is nothing great about what I did.
The outcome could have been different. And it can still be.