Eh tu, tennis?

In a summer that has stoked fair-play fans' worst fears about sports, the cloud of malfeasance has now spread over the world of men's tennis, just two weeks before U.S. Open qualifying begins.

Nikolay Davydenko, the world's No. 5-ranked player, brought suspicion to the sport last week in Poland, when he retired from a match against unseeded Martin Vassallo Arguello that drew about $7 million in wagers, 10 times the usual amount for a match of its kind.

Most of the money was on Arguello to win, even after Davydenko won the first set 6-2. Davydenko bowed out with a foot injury trailing 2-1 in the third set, and authorites voided all bets.

Davydenko has denied any wrongdoing. Nevertheless, the affair appears to bring tennis into dishonorable kinship with several other sports.

A quick roll call: NBA referee Tom Donaghy's point-shaving scandal, baseball's ongoing steroid era, multiple player arrests that have dented the NFL's shield and, perhaps most spectacularly, cycling's festival of doping, also known as the Tour de France.

Before the Davydenko contretemps, tennis, with just a few minor doping cases in its past, was an oasis from the bad behavior, as the U.S. Open, the world's best-attended annual sporting event, was ready to demonstrate.

Davydenko's potential links to bookmakers are unfortunate. On the court, he is a top-flight overachiever, a baseliner who disdains rest -- he played in 32 tournaments last year, more than any other top-10 player.

He is a no-nonsense athlete who endorsed the Prince racquet he plays with for free last year.

Davydenko is back to scratching out wins this week, reaching the quarterfinals in Montreal on Thursday.

But the episode that played out bewteen Davydenko and Arguello in Poland last week has exposed the fragility of fairness in the hyperindividual game of tennis.

Fans at the USTA National Tennis Center later this month may have trouble keeping that from their minds.