Azarenka retires from opening match due to injury at Roland Garros

Belarus' Victoria Azarenka retruns the ball to Italy's Karin Knapp during their women's first round match at the Roland Garros 2016 French Tennis Open in Paris on May 24, 2016. [Photo/Agencies]

PARIS - Two-times Australian Open champion Victoria Azarenka was forced to retire with a right knee injury from her opening match at Roland Garros on Tuesday when the fifth seed trailing 4-0 to world No 118 Karin Knapp in the decider.

The former French Open semifinalist got the early break to take a 2-1 lead, but it was her Italian opponent who took the first set 6-3 with big serving and hard-hitting shots.

In the second set, Azarenka took an early 2-0 lead and forced the third set with a 8-6 win in a tiebreaker, though the Belarusian seemed uncomfortable, calling for a medical timeout at 3-3 to nurse her right knee.

Azarenka battled tears throughout the third set before conceding at 0-4 to give Knapp the win.

Knapp, who made it to a career high of world No 23 last year, is thus through to the French Open women's singles last 64.

"I am really happy. I mean, I'm sorry for her. She had injury. But I think when she retired, we were having a great match," said the Italian.

Knapp next plays Latvia' s Anastasija Sevastova in the second round which she moves into for the first time since 2008.