Alex Dolgopolov was just behind the front lines in Kherson last month, with living conditions as far removed from the gilded environment of the tennis tour as imaginable.

Just 18 months after formally announcing the end of his career — his last match was against Novak Djokovic — home for Ukraine’s former world No 13 was an abandoned house in a burnt out village.

‘The place had mice running everywhere. There was no toilet and you had to use a hole, there’s no hot water so you have to heat some up to wash,’ he says.

Ukrainian Alex Dolgopolov enlisted in the army after retiring from tennis 18 months ago

‘It was a village where most people had left and there was just this one old lady there who fed us grapes. Not a comfort zone. Then we’d roll out from there, driving out to the front on our missions.’

It has been like this for weeks at a time for Dolgopolov, one of his country’s most successful players in recent decades. An athletic shotmaker, he played eight Wimbledons, made the Australian Open last eight and beat Rafael Nadal at Queen’s in 2015. He returned from his latest tour to the front last week and, after much persuading, is sitting in front of a zoom camera at a flat in Kyiv, where he is currently resting.

‘War is a mess,’ he says, in a neat summation of the life-changing experiences he has gone through since he joined up to fight the Russian army in the summer.

He gives a fascinating account of his new role, primarily as a drone operator in a versatile unit attached to GUR, Ukraine’s military intelligence. He speaks with a disarming matter-of-factness about killing the enemy.

The 34-year-old was one of his country’s most successful players in recent decades

While required to be deliberately vague about operational matters, his social media is already a guide to what he does. Not for the squeamish, it sometimes features video footage, taken from the sky, of Russian soldiers being blown to smithereens.

The 34-year-old…