Formerly top-ranked tennis player James Blake ended up in handcuffs Wednesday after cops mistakenly took him for an identity theft suspect, police sources said.

Blake, 35, was heading to the U.S. Open in Queens around noon to make corporate appearances for Time Warner Cable, according to the Daily News.

During that time, detectives from the Identity Theft Task Force who were investigating the purchase of cellphones using fraudulent cards were doing a controlled delivery at his hotel, the Grand Hyatt on East 42nd Street, sources said.

A suspect was taken into custody during the delivery, who then identified two individuals in the lobby of the Hyatt that he delivered cellphones to yesterday.

RELATEDSerena Williams advances in US Open, beats sister Venus

One of those two individuals was Blake, who, according to published reports, was tackled to the ground before being handcuffed.

He was released when a retired member of the NYPD informed detectives that one of the men in handcuffs was Blake, who, after confirming his ID, was let go, sources said. The second man was taken into custody.

“Once Blake was properly identified and found to have no connection to the investigation, he was released from police custody immediately. In regards to the alleged improper use of force, the police commissioner directed the internal affairs bureau to investigate.” an NYPD spokesperson said.

RELATEDPhotos: 10 most intense U.S. Open action shot faces

The African-American tennis pro, who was once ranked number four in the world, told the Daily News that the incident involved unnecessary force regardless of his race. He suffered a cut to his elbow and bruises to his leg.

"You'd think they could say, 'Hey, we want to talk to you. We are looking into something. I was just standing there. I wasn't running. It's not even close (to be okay). It's blatantly unnecessary. You would think at some point they would get the memo that this isn't okay, but it seems that there's no stopping it."