Is there a member of a royal family at the Atlanta Tennis Championships this week?

No, Prince William and Princess Kate aren’t causing the residents of Norcross to kneel.

Instead, the “Baron of Schifflange” has not only been at the Racquet Club of the South, he has been playing.

Who is the “Baron?”

It’s supposed be Gilles Muller, according to some biographical information given by the ATC’s organizers.

It turns out they were duped.

Muller is a real person. He is ranked No. 82 on the ATP Tour and defeated Kevin Anderson in the quarterfinals of the ATC on Friday, 7-6 (3), 7-6 (3).

But is he royalty?

“It’s not true,” he said laughing.

He said someone pointed it out to him earlier in the day.

According to the numerous websites (typing “Baron of Schifflange Gilles Muller” into Google results in 4,360 hits), Muller is descended from the Baron of Schifflange, who ruled the tiny European country of Luxembourg in the 18th century.

Schifflange is a real town. It is in the southern part of the country, which is sandwiched between France and Germany. While there may have been a Baron of Schifflange, there’s no mention of him on any websites about Luxembourg’s history.

Ron Cioffi, media director, for the ATC, apologized for the error.

“Based on thousands of Internet references to Gilles Muller being descended from Baron Muller of Luxembourg, we ran that fact in the Atlanta Tennis Championships program,” he said. “We worked hard to verify all our facts in our program and apologize for the error. Gilles was obviously shocked to find out just today that this reference was an accepted fact and we’re glad he found the reference humorous. We are very pleased that Muller verified that this was not correct and cleared the air here in Atlanta.”

Isner wins

John Isner blitzed Yen-Hsun Lu 6-1, 6-2 in his quarterfinal match Friday. He will face Muller at 1 p.m. Saturday in the semifinals. Isner is 1-0 against Muller, defeating him 4-6, 7-6 (6), 7-6 (7) in the second round in Atlanta last year.

“I remember that match was so tough, and I was fortunate to win,” Isner said. “He served well and is tough to break, like I am. It could come down to a point here or there. There’s a good chance we could play a tiebreaker or two as well.”

Isner is trying to accumulate enough points to earn a seed in the U.S. Open. He’s ranked No. 35 and needs to move into the top 32. Unseeded earlier this year for the French Open, Isner was bounced by top-ranked Rafael Nadal in five sets in the first round.

Fish advances

Defending champion Mardy Fish knocked off Somdev Devvarman 6-4, 6-3 to advance to the other semifinal.

Fish was ahead 5-0 and had two match points, but couldn’t finish, allowing Devvarman to come back and win three games.

“I played one bad game and rushed it,” Fish said.

Harrison advances

Ryan Harrison defeated Rajeev Ram 4-6, 6-1, 7-6 (5) in a thrilling match Friday night.

Harrison, 19, becomes the first American teenager to advance to the semifinals of an ATP event since Sam Querrey did so in Indianapolis in 2007. The win will also push Harrison into the top 100 of next week's points standings. It also marks the first time that three U.S. players are in the semifinals of an ATP event this year.

Trailing 40-30 in the third set, Harrison saved match point with an ace and then won two more points to tie the set, 6-6. He led the tiebreaker 5-1, only for Ram to battle back and tie it 5-5. Harrison won the sixth point with a volley.

Ram hit three of his best shots in the final game -- one kissed the sideline on the right, the other was a hard, flat BB that barely cleared the net toward the middle, and the last was another hard groundstroke to the left. Harrison returned them all, with the last clipping the net and bounding over Ram, who seemed poised to hit a backhand winner. Harrison seemed embarrassed by the winner, holding up an apologetic hand to Ram, who stood with his head back in disbelief.

It was an odd week for Ram. He is mostly known for his play in doubles and is one-half of the defending champion doubles team that was knocked out in the first round.

He was 0-1 in singles this year, failing to make it out of qualifying in nine tournaments this year.