Andre Agassi is shocked by Armstrong doping scandal. At Australian open presser, Agassi speaks about doping scandal and the men's final with Andy Murray and Novak Djokovic.

Andre Agassi is one of the greatest tennis players of all-time, but even he knows what it's like to be involved in controversy. The tennis great spoke out about the Australian Open as well as Lance Armstrong on Friday, saying that he was shocked about the entire doping scandal.

Agassi was back as the Australian Open for the first time since he retired in 2006 and spoke at a press conference about Armstrong as well as the men's game overall. He also linked back the Armstrong issues back to tennis, speaking about testing within his own sport.

HERE is an Australian Open finals prediction.

"It feels long overdue,'' Agassi said Friday when he walked into the news conference room at Melbourne Park.

The 42-year-old tennis star said that he was glad that he finished his career before the so-called Big Four started up in the sport. He said he "marvels" at the way they play and about how quickly they can recover after five-set matches due to advanced training.

"It's just a different standard of tennis,'' said the eight-time Grand Slam winner. "It's different rules of engagement when guys can do what these guys can do. It means the game has gotten a lot better. You know, Fed raised it. Nadal matched and raised it. Djokovic, for that intense little period of time, even raised it. When I see those top three guys, I see what history will say is the golden age of tennis. You're talking about arguably the three best guys.''

Agassi said he firmly believes Murray belongs in the conversation at the top, especially after his five-set win against Roger Federer on Thursday.

"He believes now, and so now you're talking about four guys,'' he said. "They've separated themselves from the field.''

As for predictions, Agassi decided that Djokovic was going to make it three Australian Open wins in a row.  Agassi won in Melbourne four times, the last coming in 2003 when he defeated Rainer Schüttler.

According to SI.com, When asked how he would have tried to beat a player of Djokovic's caliber, Agassi wisecracked, "I would have probably gotten in a fight with him in the locker room before the match. I might have had a chance.''

Later on, Agassi spoke about the Lance Armstrong scandal and touched on issues regarding drug testing in tennis. He said that the first reaction to Armstrong's confession in an interview last week with Oprah Winfrey was "shock, hard to stomach, sadness, disappointment. I think 'anger' is a fair word.

"I was certainly one of those that flat-out believed him that long period of time,'' said Agassi, who met Armstrong on numerous occasions. "The thought of it not being the case was unconscionable to me.''

Agassi and Armstrong shared a sponsor in Nike and also were part of a group of athletes involved in charity work who founded Athletes for Hope.

Agassi had substance issues himself in the past, admitting in his 2009 autobiography "Open,'' to using crystal meth during his playing days in the late 1990s and lying about it to tennis authorities after failing a drug test, telling them he unwittingly consumed a spiked drink. Agassi said that any extra transparency in the testing is a benefit, especially for young players who need to be held accountable at times.

"It would have kept me from destroying a few years of my life,'' he said. "That's what I did to myself with the use of the recreational, destructive substance of crystal meth. Anything that can protect the integrity of the sport, and those that aren't cheating should absolutely be considered. The more (testing), the better as far as I'm concerned.''

According to ESPN.com, the ATP first started drug-testing players in the mid-1980s, then oversaw the anti-doping program, a system that changed after the current international anti-doping infrastructure was born in 1999 with the creation of the World Anti-Doping Agency.

The International Tennis Federation oversees testing for both the men's and women's tours now. Agassi said that tennis has always been a leader in testing and was asked about possible additions of out-of-competition testing and blood testing.

"Anything that can protect the integrity of the sport and those that aren't cheating should absolutely be considered,'' Agassi said. "I mean, what is the downside? You start looking at the inconvenience of players. Maybe that turns into an issue at some point, I would imagine. But unfortunately, you know, we're at a day and age where the more transparency you have in all of it, the better off it all is and the better off these athletes are. The more the better, as far as I'm concerned. The stricter, the better; the more transparency, the better; the more accountability, the better.''

Agassi is considered to be one of the best American tennis players of all-time and during his career it was more of a Big Two than a Big Four along with fellow American Pete Sampras, who is known to keep a low profile since retiring.

During his career, Agassi won eight Grand Slams, including two U.S. Open's, as well as an Olympic gold medal. He finished with a career 870-274 record and likely would have had more majors had it not been for the strong play of his rival Sampras. Agassi is currently married to women's tennis great Steffi Graf, with whom he has two children.

Agassi has been prominent in philanthropic causes during and after his career, including through his Andre Agassi Charitable Association, which was founded in 1994 to help young people in Las Vegas, which is where he grew up. He has built tennis academies in the city and has also started a number of tennis and child-related programs to help youths in the community.