Roger Federer refused to get drawn into the debate about wild cards being handed out to players coming back from doping bans.

The person in question was Maria Sharapova, who will return to the tennis court when her 15-month ban comes to an end at the end of April. She has been granted wild cards by tournaments in Stuttgart, Rome and Madrid.

The Russian former world number one failed a drug test at the 2016 Australian Open as she tested positive for meldonium. Sharapova was subsequently banned for two years by the International Tennis Federation (ITF), but it was later reduced to 15 months by the Court of Arbitration for Sport (CAS).

Wimbledon are still debating whether to give the 2004 champion a wild card for this year's championships in July. The issue of handing out wild cards has caused a stir with world number one Andy Murray suggesting that dopers should not be handed wild cards and should be made to earn their spot on tour. Federer, however, refused to be drawn into the debate and shied away from giving a definitive answer.

"Could see it either way, depending on who you are, and don't know if it matters what the cause was for being banned, because at the end, it's all sort of the same. Banned is banned, you know. It's a tough one. I really don't know what to answer on that one, to be quite honest," Federer said as quoted by tennisworldusa.org

Federer, meanwhile, was still at a loss for words to explain his shock second round loss at the Dubai Tennis Championships to unknown Russian Evgeny Donskoy. The Swiss ace, who was playing his first tournament since his Australian Open triumph, had three match points in the second set, but failed to convert them and eventually lost 3-6, 7-6, 7-6.

"Don't know where to start, really. I guess it was good to save set point in the second set. Gave me a chance to stay in the second set after that. And then in the breaker, I served well. He clocked one at 6-4, I think. And then again one to get break point in the third. Those are the only two he really hit for winners.

"It was bad timing that I went into that corner at the time that maybe he was stretching perfectly for it. Regardless, I had my chances. I should somehow close it out. Don't know how it got away, but he did very well, and yeah, it's a rough one, for sure," the former world number one explained.