Roger Federer said he was saddened by the Lance Armstrong drugs scandal, on Saturday, as players lined up to criticise the disgraced cyclist and Andy Murray backed tougher controls for tennis.
"What a sad story," said 17-time Grand Slam champion Federer, when asked about Armstrong at the Australian Open.
"Look, I mean, I don't know what to say. It just really saddens me to see that someone did this for such a long time. Obviously he's hurt his sport in a big way, even though he helped it in the beginning.
"But now the burden they live under, all other sports maybe as well. I'm an active athlete right now, and it's not fun times really to be in sports to a degree.
"I guess all I needed to see was the first few minutes of the interview and then I knew what was the deal, and the rest I don't really care. It's just very saddening, really, this story, to be honest."
While Serena Williams also called the saga "sad", and women's number one Victoria Azarenka said Armstrong "deserves everything he gets", Murray said tennis may need to tighten its anti-doping procedures.
"I think it's something that all sports are now trying to improve their doping controls and make it better, make sure that every sport's as clean as possible," the British major-winner said.
"If that's more blood testing or the biological passports, that's something we need to do and improve in tennis, as well."
Drug cases are rare in tennis but its anti-doping system, which relies largely on urine rather than blood tests, has been criticised as outdated, and some suspicions have been voiced about leading players.
Men's number one Novak Djokovic Friday said he had not been blood-tested for six or seven months, although Murray said his blood was examined between four and six times a year.
Biological passports are used in some sports including cycling to provide a running record of each athlete's test results, to detect unusual variations.
After Djokovic said Armstrong should "suffer for his lies" following his long-awaited doping confession, Azarenka also had harsh words for the seven-time Tour de France champion.
"I think he deserves everything he gets. You cannot go through the stuff and be a hero in the end of the day. You cannot lie. You cannot cheat," said the Belarusian.
Williams said she was "glued" to the TV interview, adding that the Armstrong case would now bring many top athletes under suspicion.
"I think as an athlete, as someone that works really, really hard since I was four or three, I think it's a sad day for all athletes in general," she said.
Williams added: "Unfortunately, I think a lot of people now look and are like, OK, if somebody that great, what about everyone else in every other sport?"