Tennis icons Steffi Graf and have pinpointed the one golden rule they abide by to make sure their marriage works. Graf's legendary career from 1982 to 1999 saw her clinch a staggering 22 Grand Slams, being the only player ever to clinch each of the majors at least four times.

The German married men's star Agassi in 2001, with the American enjoying a spectacular career himself between 1986 and 2006, where he won eight Grand Slams. The couple have gone on to have two children: Jaden Gil Agassi, aged 23, and Jaz Elle, aged 21. A quarter of a century after tying the knot, their relationship is still going strong - and a key of part of that is the increasingly popular sport of pickleball.

During the lockdowns brought about by Covid-19 in the spring of 2020, the Agassi family took up pickleball just for fun and have been hooked ever since.

Graf admitted that the sport, which is similar to tennis but is played on a doubles badminton court, "filled a huge" tennis-shaped gap in their lives after retirement. And she revealed the one key reason that they have been able to sustain their marriage while still competing.

Graf told in an interview: "We don't play against each other. We prefer to be on the same side of the court." Agassi interjected: "We like that pickleball is a community-oriented sport. People who play pickleball also improve quickly."

He added: "We really want to spread the game. When we're not traveling, we practice a lot of pickleball. Since we both play, it's fun to do it together."

On Saturday, April 12, Agassi hosted the first-ever Agassi Open Play Day at Life Time Green Valley to mark National Pickleball Month. The event was also mirrored at more than 100 Life Time athletic clubs around the United States at the same time.

Earlier this year, they won the Pickleball Slam title for the third consecutive time, beating Andy Roddick and Eugenie Bouchard to take home the whopping $1million (£743,000) prize after three matches and a tiebreak round. The power couple balances their sporty lifestyle with spending time with their kids and their respective partners, even going on triple dates.

Agassi explained: "We had a great date night the other night where it was me, Steffi, my son and Catherine, his girlfriend, and Jaz, our daughter, and her boyfriend Parker, and it was like a triple date and we all just went out and sat and talked.

"We feel like peers around them, we respect them, we seek their opinion on things, they're not hesitant to ask us our perspective on what they're going through, so it really feels like a healthy season in life."