What's left for a man who has won three Olympic sprint titles back-to-back?

Win all three again, of course.

Seven-time champion AC Milan avoided another early-season hiccup by reaching the group stage of the Champions League with a 3-0 win over PSV Eindhoven, and Celtic produced a stunning comeback to join them on Wednesday.

After a 1-1 draw in a tense first leg in the Netherlands, Kevin-Prince Boateng scored twice and Mario Balotelli added another to ensure Milan won the playoff 4-1 on aggregate and advanced to Thursday's draw.

James Blake walked off the court at the U.S. Open for the last time as a singles player early Thursday morning after blowing a two-set lead and losing in a fifth-set tiebreaker.

The 33-year-old American fell 6-7 (2), 3-6, 6-4, 7-6 (2), 7-6 (2) in the first round to Ivo Karlovic.

After her latest early Grand Slam exit, Venus Williams was asked what the future holds for her at the U.S. Open.

In one breath, Williams brushed aside the unspoken reference to retirement, saying, "I definitely want to come back for the atmosphere."

Lionel Messi missed a late penalty attempt before Barcelona clinched the Spanish Super Cup despite being held to a 0-0 draw by 10-man Atletico Madrid on Wednesday.

Messi had a chance to put the result beyond doubt in 89th but fired his penalty kick off the crossbar to finish a forgettable night for the Argentina star. Barcelona eventually claimed the trophy on away goals following the 1-1 draw in the opening leg last week.

Marijuana is the most popular illegal drug used worldwide, but addictions to popular painkillers like Vicodin, Oxycontin and codeine kill the most people, according to the first-ever global survey of illicit drug abuse.

In addition to cannabis and opioid painkillers, scientists analyzed abuse of cocaine and amphetamines in 2010, largely based on previous studies. Ecstasy and hallucinogens weren't included, because there weren't enough data. The researchers found that for all the drugs studied, men in their 20s had the highest rates of abuse. The worst-hit countries were Australia, Britain, Russia and the U.S. The study was published online Thursday in the journal, Lancet.

Scientists have found a compelling clue in the quest to learn what causes age-related memory problems, and to one day be able to tell whether those misplaced car keys are an early warning of Alzheimer's.

Wednesday's report offers evidence that age-related memory loss is a distinct condition from pre-Alzheimer's — and offers a hint that what we now consider the normal forgetfulness of old age might eventually be treatable.

A military court on Wednesday sentenced Nidal Hasan to death for the 2009 shooting rampage at Fort Hood, giving the U.S. Army psychiatrist a path to the martyrdom he seemed to want in the attack on unarmed fellow soldiers.

Hasan could become the first U.S. soldier executed in more than half a century. But because the military justice system requires a lengthy appeals process, years or even decades could pass before he is put to death.

England's cricketers have apologized after team members were seen urinating on the pitch at The Oval as they celebrated the Ashes series victory over Australia on Sunday.

In a statement issued Wednesday, the team responded to criticism by accepting "we got carried away (in) the euphoria of winning such a prestigious series and accept that some of our behavior was inappropriate."

A player from a third-division Argentine club has died of a heart attack during a match.

Club Deportivo Laferrere announced that Hector Sanabria collapsed in the 29th minute of a game against General Lamadrid on Tuesday — a day before his 28th birthday.