She won 22 Grand Slam titles in a 16-year professional career, the second-most behind Serena Williams (23) since the start of the Open Era in 1968, and the third-most in history behind Margaret Court (24).

Steffi Graf was ranked world No. 1 for 377 weeks and won a total of 107 career titles.

However, there is one achievement in her career that stands out. In 1988, a then 19-year-old Steffi Graf won the first-ever Golden Slam.

A term coined by the media, the Golden Slam is when a player wins all four Grand Slams – the Australian Open, French Open, Wimbledon and US Open – in addition to the Olympic gold medal. Only 12 players have managed the feat in their career to date but the German remains the only player in tennis history – male or female – to achieve the feat in a single year.

Graf is also one of the only four who have managed a Golden Slam in singles tennis. Andre Agassi, Serena Williams and Rafael Nadal are the other three.

It is as daunting as it sounds and requires great effort and adaptability from a tennis player to triumph across hard courts, grass courts and clay courts, all within months of each other.

Steffi Graf, though, had those qualities in abundance – she is the only player in history to have won each of the Grand Slams at least four times.

Here’s how Steffi Graf became tennis’ Golden Slam winner in 1988.

1988 Australian Open

Having won her first Grand Slam title, the French Open in 1987, and risen to world No.1 for the first time, Steffi Graf entered the 1988 Australian Open as the top seed.

The German was in form, winning the first four rounds in straight sets and dropping only 13 games.

Steffi Graf then beat defending champion Hana Mandlikova 6-2, 6-2 in the quarter-finals before ousting compatriot Claudia Kohde-Kilsch 6-2, 6-3 in the semis.

With such devastating form coming into the final, Steffi Graf beat third seed Chris Evert 6-1, 7-6 to claim her first Australian Open crown. It would prove to be the last of Evert’s six Australian Open final appearances.

1988 French Open

Defending champion Steffi Graf was seeded first again at the French Open and swiftly went about beating her opponents, dropping only 11 games until the semi-finals.

Up against fourth-seeded Argentine Gabriela Sabatini in the last four, Steffi Graf faced her first real test, but overcame it with ease, winning 6-3, 7-6 to go through to the final.

In one of the most dominating performances in Grand Slam finals, Steffi Graf whipped Belarus’ Natasha Zvereva 6-0, 6-0 to claim her second-consecutive French Open crown. It lasted just 34 minutes and is the only ‘double bagel’ Grand Slam final.

1988 Wimbledon

Switching to the rapid grass courts for the year’s third Grand Slam at Wimbledon, top-seeded Steffi Graf needed no time to adapt. She won all her matches in straight sets and dropped only 17 games in her run to the final.

In the final, Steffi Graf faced her biggest challenge – up against record six-time defending champion, the legendary Martina Navratilova.

The final began well for Graf as she took a 5-3 lead but Navratilova hit back, winning four games in a row to win the first set.

Navratilova also won the first two games of the second set to take a 2-0 lead and looked on course for a seventh-straight Wimbledon title.

However, a determined Steffi Graf hit back in ferocious fashion, bringing out her famous forehands and groundstrokes to win six games in a row to take the second set and force a decider.

With the momentum firmly on her side, Graf then went on to win the third set 6-1 and claimed her first Wimbledon title, ending Navratilova’s stronghold.

Steffi Graf also won her only Grand Slam doubles title at the 1988 Wimbledon, taking the women’s doubles title partnering Gabriela Sabatini.