World number one Tiger Woods insists compulsory drug testing is essential to ensure a clean sport in the wake of the one-year ban handed out to American journeyman Doug Barron.

The PGA Tour announced earlier this week that Barron had violated the anti-doping policy on the use of performance-enhancing substances, becoming the first player to be banned after golf introduced testing in June last year.

The European Tour have insisted there have been no failures in Europe, with the anti-doping programme continuing at this week's World Golf Championships-HSBC Champions in Shanghai.

Woods said of Barron's ban: "It's unfortunate, but that is one of the reasons why we have the policy to make sure no-one does anything that's improper for the game of golf and I think that it is great that we have the policy in place.

"I don't know if he tested for performance-enhancing or recreational, but the whole idea is to keep our sport clean and that is why we created the policy and it has been executed and unfortunately one player didn't obey the policy."

Further details of Barron's case have not been announced.

The 40-year-old, who has never won in 238 appearances on the PGA Tour, has apologised but insisted he never intend to gain an unfair advantage.

Barron was playing on the Nationwide Tour this year on a medial exemption and is known to have taken medication in the past for several conditions.

World number two Phil Mickelson, who is also in the field in Shanghai this week, was sympathetic towards Barron.

"I don't know the details of it. I know that we have been tested numerous times throughout the last year and a half since the policy has been in place. But I don't know the specifics," he said.

"I would venture to say that there was some sort of mix-up. Just knowing my fellow players, I don't think they would do anything to try to skirt the rules.

"I've never really thought of Doug Barron as an Arnold Schwarzenegger-type body. So I'm guessing, not knowing any details, that there was probably some kind of confusion or misunderstanding."