Ever since I came face to face with a gaudily-dressed, frosted-haired 17-year-old upstart with a service return most grown champions would die for, Andre Agassi was a player apart from the rest. He’s always had the ability to surprise, to shock, if you like. So I was not surprised that he confessed to taking drugs this week — though I was amazed that they were of the recreational variety.

Despite his rebellious image in those early days, Agassi was never a rock’n’roller who liked to let rip now and again. He didn’t even like Guns N’ Roses or Van Halen, like most of his American contemporaries, saying he much preferred the soft, sugary jazz of Kenny G.

Suspicion among the other players had long been rife that he may have used some substances to help him become one of the fittest and strongest guys around, although there was never any proof. There were some dubious circumstances, none more than his early-morning withdrawal from the defence of his title at the 2002 Australian Open, citing a wrist injury.

Back then I remember Australian Sports Drug Agency boss John Mendoza maintaining drugs were a major issue for the sport and claiming the ATP Tour was covering up positive results. I also recall Magnus Norman, a French Open finalist, writing in a book that was only ever printed in Swedish that there were suspicions about Agassi being one of the six names that never came to light after being found to have tested positive by the ATP. Agassi had been locked away for hours with the tour hierarchy in Melbourne and a knowing look appeared on many faces in the locker room. I guess we will never know the answers to those questions, although I agree with this week’s demands that those in the ATP who know the answers owe it to the sport to finally come clean.

Back to the youthful Agassi who, before he lost all that hair, became something of a philosopher and collected just about every major prize the sport could offer. I will never forget that match back in 1987. It was my first tournament back on the ATP Tour after winning Wimbledon and I was feeling on top of the world, but at Stratton Mountain in Vermont Agassi put me in my place by beating me in two sets.

But why did he get involved with a dangerous substance such as crystal meth, which can be a killer, and why did he choose to reveal the fact 12 years on? From my experience and perception, recreational drugs on the men’s circuit wasn’t rife then and certainly isn’t now. Sure, there were well-known players who got involved with cocaine, such as Vitas Gerulaitis and, after he retired, Bjorn Borg.

I have admitted to using it in some of my regrettably lower moments, but not when I was in competition. John McEnroe made a few admissions in his book, Mats Wilander got caught but that was right at the end of his career and there is the much more recent Richard Gasquet case. There is not a gaggle of drug pushers hanging around the tour hotels or players’ lounges. The drug testing under the auspices of the World Anti-Doping Agency is rigid; some say intrusive. You wouldn’t be able to get away with anything. But it’s what is needed to keep tennis clean.

Things were so lax when I was playing in the late 1980s and 90s. I was tested just once in all that time, in Key Biscayne, Florida, and got a clean billing. In my view, performance-enhancing drugs weren’t an issue in tennis back then. I was never offered this or that to aid my recovery or make me that bit stronger or faster. A guy who pops something illegal in a bid to make himself better than his opponent is a cheat. The reaction to that would be a lot worse in the locker room than if somebody got busted for recreational drugs.

I know what Agassi went through. I’ve been there. You’re injured and can’t play, you see your ranking dropping like a stone and wonder how you are going to get in the big tournaments. You are lonely, and remember, his marriage to Brooke Shields was going through a tough time. When somebody offers you a little something to make that anguish go away, it’s tempting.

The problem is that drugs, unlike alcohol, are illegal. People such as George Best and Paul Gascoigne were treated with pity rather than being banned from the game. Plus the fact is we play a lonely sport — you haven’t got teammates to put their arms around your shoulder.

What is my take on what happened in 1997 when Agassi told ATP tour officials he had “unwittingly” ingested the drug in a “spiked” drink? Well, Agassi lied, but were the powers-that-be going to be too hard on him? Men’s tennis was in a terrible state. The game had become predictable and unentertaining. Crowds were dropping, revenue suffering. It was crisis time. The sport needed every major personality it had and Agassi was still a huge name. Had he copped a two-year ban the history of the game would have been very different. Almost certainly, he wouldn’t have been the first man since Rod Laver to collect all four Grand Slam titles, he wouldn’t have had that great rivalry with Pete Sampras, he wouldn’t have gone on to become that iconic figure, still playing top-flight tennis at 36. He wouldn’t have been invited by the All England Club to play the match to unveil Centre Court’s new roof. They don’t like druggies down at Wimbledon. Would we here in Britain be getting so excited about the Barclays ATP World Tour Championships coming to the London O2 Arena in a couple of weeks’ time with all the top names?

Most crucially, would top-flight tennis have survived those tough times without Andre Agassi?

Tennis players and recreational drug use

Vitas Gerulaitis

A poorly-kept secret towards the end of his career, by the time of his retirement, it was common knowledge that the American had been a prolific cocaine user throughout his career

Pat Cash

The 1987 Wimbledon champion revealed the extent of his drug abuse in his 2002 autobiography, including the admission that, “when I played my first time at Wimbledon, I'd keep a joint under my pillow and have a smoke every night. It calmed me down."

Jennifer Capriati

In 1993 the child prodigy was arrested for shoplifting and six months later, was arrested for marijuana possession in a $50-a-night Florida motel. A teenage companion who pulled into the hotel parking lot driving Capriati’s car was caught with crack and later told The Sun he smoked crack with Capriati.

Martini Hingis

After several surgeries and long recuperations, Hingis returned to the tour in 2006 but, on 1 November 2007, after climbing back to world number six, she announced her retirement from tennis while admitting she had tested positive for cocaine during Wimbledon in 2007. She denies taking the drug.

Richard Gasquet

The Frenchman tested positive for cocaine in March 2009 but escaped suspension after explaining that he had inadvertently consumed the drug after kissing a woman – “Pamela” - who had consumed it at a party.

Mats Wilander

Along with Karel Novocek, the Swedish former world number one tested positive for cocaine at the 1995 French Open. Both were banned for three months and ordered to return prize money and forfeit rankings points.

Lourdes Domínguez Lino

To date, the Spanish player is the only woman to be suspended from the WTA when she tested positive for cocaine in March 2002

Yannick Noah

In 1981, Yannick Noah admitted smoking marijuana before matches, but insisted that amphetamines were a greater problem because they were performance enhancers.