Serena Williams’ quest for a French Open title just got easier

Hours after No. 3 Angelique Kerber was upset in the opening round, another top women’s player exited the French Open field at Roland Garros on Tuesday.

Fifth-seeded Victoria Azarenka was forced to retire midway through the third set against Karin Knapp after a right knee injury proved to be too much to bear.

The early exits of Azarenka and Kerber should make life easier for defending French Open champion and No. 1 seed Serena Williams, as they were both in her half of the draw. Williams started her title defense with a 6-2, 6-0 win over Magdalena Rybarikova on Tuesday.

Azarenka was in obvious pain during her match, but tried to fight through it.

Knapp, who beat Azarenka at Roland Garros nine years ago, came out firing and took the first set 6-3.

Azarenka began to break down during the second set, and took a medical timeout leading 4-3 in the second set.

Knapp almost finished Azarenka off in the second set, leading 6-5 in the tie-break. But Azarenka fought back, saving the match point with a forehand winner and pushing on to send it to a third.

Azarenka was almost completely immobile in the third set, falling behind 3-0 and fighting through tears. She called for her trainer once more to try and complete the match, but she couldn’t.

Azarenka, a two-time Australian Open champion, had won titles this year at Indian Wells and the Miami Open. She had pulled out of this month’s Madrid Open with a back injury and lost in straight sets in the second round of the Italian Open.